Fixed critical memory leak from EVAL.
Fixed critical memory leak from EVAL.

Multiple missing calls to lua_pop prevented the error handler function
pushed on the stack for lua_pcall() to be popped before returning,
causing a memory leak in almost all the code paths of EVAL (both
successful calls and calls returning errors).

This caused two issues: Lua leaking memory (and this was very visible
from INFO memory output, as the 'used_memory_lua' field reported an
always increasing amount of memory used), and as a result slower and
slower GC cycles resulting in all the CPU being used.

Thanks to Tanguy Le Barzic for noticing something was wrong with his 2.8
slave, and for creating a testing EC2 environment where I was able to
investigate the issue.

pkdevbox/redis,spearhead-ea/redis,magastzheng/redis-3.0-annotated,yossigo/redis,hgl888/redis,duanx/redis,rogerlz/redis,mgk/redis,gaoxianglong/redis,gechong/redis-3.0-annotated,yybirdcf/learn-redis,yossigo/redis,seppo0010/redis,rouzier/redis,ramonsnir/redis,rouzier/redis,190235047/redis,qiyang0221/redis,simplestbest/redis,mengyou0304/redis,j0hnma/hszredis,AplayER/redis,HouKangkang/redis-3.0-annotated,huyuezheng/redis,josiahcarlson/redis,timothyohare/3rdPartySrc-redis,190235047/redis,JoeWoo/redis,Wangyao14cyy/redis,splitice/redis,LongXQ/redis,moonbingbing/redis-3.0-annotated,AplayER/redis,fankeke/redis-3.0-annotated,jbochi/redis,fengshao0907/redis-3.0-annotated,zhaobo1023/redis-3.0-annotated,soveran/redis,himoca/redis,Aliceljm1/redis,zy416548283/redis-3.0-annotated,gilala/redis,shreesundara/redis,miaoyc1989/redis-3.0-annotated,Hailei/redis,sunheehnus/redis,jasonkying/redis,spinlock/redis,zhoudayang/redis,cloudrain21/redis,vincent-vivian-liu/redis,soloestoy/redis,holstvoogd/redis,z-fork/redis,weizijun/redis,ton31337/redis,linfangrong/redis,fengshao0907/redis,qiyang0221/redis,pcarrier/redis,ksarch-saas/redis,abhiklodh/redis,davidradunz/redis,RepmujNetsik/redis,adamweixuan/redis-3.0-annotated,pedigree/redis,mengyou0304/redis,0x55/redis-3.0-annotated,jbochi/redis,healerkx/redis,riyan8250/redis,universsky/redis,maodeyi/redis_lua,itugs/redis,slfs007/mk-redis,mattsta/redis,LongXQ/redis,tanghaodong25/redis,ton31337/redis,wuyu201321060203/redis-3.0-annotated,guker/redis,190235047/redis,mumingv/redis,hawkchch/redis,4396/redis,twskipper/redis,nuxeh/redis,seppo0010/rlite-server,ErikDubbelboer/redis,wenxueliu/redis_comment,arijitvt/redis,timothyohare/3rdPartySrc-redis,dongqifan2/redis-3.0-annotated,StevenTsai/redis,programmecat/redis,tjschuck/redis,ipmobiletech/redis,pmem/redis,flashbuckets/redis,seppo0010/rlite-server,gechong/redis-3.0-annotated,wprice/redis,antirez/redis,StevenTsai/redis,citusdata/redis,shshlzh/redis-3.0-annotated,charsyam/redis,zguangyu/redis,weizijun/redis,GitHubMota/redis,SummonY/redis,citusdata/redis,seppo0010/redis,zguangyu/redis,alenslan/redis,mumingv/redis,izhoujie/redis,louisliangjun/redis,a-pavlov/redis,adamweixuan/redis-3.0-annotated,zhcy/redis,shshlzh/redis-3.0-annotated,duanx/redis,charsyam/redis,ouyangkongtong/redis,jasonkying/redis,nilyang/redis-tdd-annotation,netroby/redis,timothyohare/3rdPartySrc-redis,soveran/redis,wprice/redis,oranagra/redis,janekmi/redis,zguangyu/redis,wujf/redis,idning/redis,Sciumo/redis,mumingv/redis-3.0-annotated,mcanthony/redis,aim-for-better/redis,takeshineshiro/redis,ouyangkongtong/redis,j0hnma/szredis,maodeyi/redis_lua,linfangrong/redis,zczhuohuo/redis,iandyh/redis,4396/redis,kmiku7/redis,josiahcarlson/redis,devaos/redis,PKRoma/redis,narma/redis,simplestbest/redis,YongMan/redis,colstrom/redis,atreeyang/redis,fengshao0907/redis-3.0-annotated,MSOpenTech/redis,a-pavlov/redis,jbochi/parallel_redis,ncopa/redis,huangz1990/experiment-redis,GitHubMota/redis,gaoxianglong/redis,mgk/redis,zhcy/redis,nuxeh/redis,arijitvt/redis,clamoriniere1A/redis,hedisdb/hedis,atreeyang/redis,jbochi/parallel_redis,j0hnma/hszredis,wangyikai/redis,xuguruogu/redis,darksideofthemoo/redis-histogram,sunlianqiang/redis-3.0-annotated,mverrilli/redis,PKRoma/redis,dongqifan2/redis-3.0-annotated,Soledad89/redis,blackmady/redis,PKRoma/redis,hedisdb/hedis,jxwr/redis,gilala/hredis,mingyaaaa/redis,programmecat/redis,guker/redis,citusdata/redis,HouKangkang/redis-3.0-annotated,MSOpenTech/redis,aim-for-better/redis,yybirdcf/learn-redis,ketor/redis,mumingv/redis,nnog/redis,allengaller/redis,neomantra/redis,brg-liuwei/redis,rogerchina/redis,ncopa/redis,mverrilli/redis,pkdevbox/redis,seandsky/redis,seppo0010/redis,itamarhaber/redis,holstvoogd/redis,ErikDubbelboer/redis,cusspvz/redis,OmarQunsul/graph-redis,CodeJuan/redis,allengaller/redis,0x55/redis-3.0-annotated,flashbuckets/redis,GitHubMota/redis,riyan8250/redis,gilala/redis,MOON-CLJ/redis,ituncle/redis,zhiliaoniu/redis,mverrilli/redis,SyntaxStacks/redis,ksarch-saas/redis,wprice/redis,pcarrier/redis,z-fork/redis,yuzhangjob/redis-3.0-annotated-unstable,takeshineshiro/redis,riyan8250/redis,kaushik94/redis,yuzhangjob/redis-3.0-annotated-unstable,OmarQunsul/graph-redis,zhiliaoniu/redis,kaushik94/redis,WorkingOfTimtohyZhang/redis-3.0-annotated,ReadCode/redis-3.0-annotated,sunlianqiang/redis-3.0-annotated,janekmi/redis,itamarhaber/redis,spearhead-ea/redis,huyuezheng/redis,moonbingbing/redis-3.0-annotated,louisliangjun/redis,hgl888/redis,MSOpenTech/redis,wuyu201321060203/redis-3.0-annotated,weizijun/redis,AALEKH/redis,ttuna/msot-redis,wujf/redis,francischan714/redis,MasahikoSawada/redis,miaoyc1989/redis-3.0-annotated,qiyang0221/redis,shining-yang/redis,buobao/redis-3.0-annotated,louisliangjun/redis,NBSW/redis,ofirluzon/redis,hawkchch/redis,ton31337/redis,july2993/redis,seandsky/redis,holstvoogd/redis,MSOpenTech/redis,allengaller/redis,hedisdb/hedis,badboy/redis,gilala/redis,cloudrain21/redis,ton31337/redis,ouyangkongtong/redis,hedisdb/hedis,ctripcorp/redis,healerkx/redis,ipmobiletech/redis,brg-liuwei/redis,gilala/hbjredis,ttuna/msot-redis,twskipper/redis,HeartSaVioR/redis,Markgorden/redis,francischan714/redis,ytjiang/redis,Wangyao14cyy/redis,gilala/redis,haima-zju/redis-3.0-annotated,healerkx/redis,izhoujie/redis,fankeke/redis-3.0-annotated,oranagra/redis,rrsean/redis-3.0-annotated,mengzhejin/RedisStudy,soloestoy/redis,ctripcorp/redis,neomantra/redis,xuzhezhaozhao/redis_reading,NBSW/redis,twskipper/redis,soloestoy/redis,hgl888/redis,ituncle/redis,xujunhai1991/redis,modulexcite/redis,universsky/redis,YuraLukashik/redis,pkdevbox/redis,whille/redis-3.0-annotated,Aaron1992/redis,hornen/redis,july2993/redis,narma/redis,vincent-vivian-liu/redis,brg-liuwei/redis,nnog/redis,roth1002/redis,Aaron1992/redis,Wangyao14cyy/redis,onlymellb/redis-3.0-annotated,mumingv/redis-3.0-annotated,zhaobo1023/redis-3.0-annotated,harrisonfeng/redis,dreamquster/redis,taoguan/redis,iandyh/redis,xlzhan/redis,oranagra/redis,ipmobiletech/redis,xuguruogu/redis,rogerlz/redis,gaoxianglong/redis,hornen/redis,shshlzh/redis-3.0-annotated,GrimDerp/redis,tjschuck/redis,buobao/redis-3.0-annotated,drinkthere/redis-3.0-annotated,pmem/redis,ytjiang/redis,alenslan/redis,july2993/redis,YongMan/redis,shshlzh/redis-3.0-annotated,cusspvz/redis,modulexcite/redis,unasm/redis-3.0-annotated,badboy/redis,flashbuckets/redis,mingyaaaa/redis,ouyangkongtong/redis,j0hnma/szredis,zhcy/redis,wujf/redis,shining-yang/redis,h0x91b/redis,supasate/redis,kmiku7/redis,slfs007/mk-redis,moonbingbing/redis-3.0-annotated,pedigree/redis,mattsta/redis,j0hnma/szredis,spinlock/redis,programmecat/redis,soloestoy/redis,simplestbest/redis,tzq668766/redis-3.0-annotated,mattsta/redis,CodeJuan/redis,netroby/redis,YuanZhewei/redis,shining-yang/redis,tellapart/redis,YuraLukashik/redis,zhcy/redis,jackyan/redis,LongXQ/redis,supasate/redis,itamarhaber/redis,seandsky/redis,modulexcite/redis,thomasdarimont/redis,maodeyi/redis_lua,190235047/redis,seppo0010/rlite-server,splitice/redis,onlymellb/redis-3.0-annotated,fengshao0907/redis-3.0-annotated,pmem/redis,cnbin/redis,iandyh/redis,zhiliaoniu/redis,colstrom/redis,zczhuohuo/redis,ketor/redis,csuhawk/redis,ncopa/redis,fengshao0907/redis,neomantra/redis,Aliceljm1/redis-3.0-annotated,dreamquster/redis,twskipper/redis,gilala/hredis,tzq668766/redis-3.0-annotated,kensou97/redis,linfangrong/redis,gilala/hredis,adamweixuan/redis-3.0-annotated,elkingtonmcb/redis,sunlianqiang/redis-3.0-annotated,tanghaodong25/redis,darksideofthemoo/redis-histogram,hornen/redis,xujunhai1991/redis,cnbin/redis,abhiklodh/redis,idning/redis,jxwr/redis,dayuoba/redis,rrsean/redis-3.0-annotated,Markgorden/redis,JoeWoo/redis,clamoriniere1A/redis,SyntaxStacks/redis,jingjidejuren/redis,zhaobo1023/redis-3.0-annotated,mgk/redis,SyntaxStacks/redis,ReadCode/redis-3.0-annotated,colstrom/redis,darksideofthemoo/redis-histogram,vincent-vivian-liu/redis,neomantra/redis,Soledad89/redis,xuzhezhaozhao/redis_reading,xujunhai1991/redis,ituncle/redis,fengshao0907/redis,huyuezheng/redis,jbochi/redis,devaos/redis,CodeJuan/redis,xlzhan/redis,jxwr/redis,atreeyang/redis,ErikDubbelboer/redis,takeshineshiro/redis,mengzhejin/RedisStudy,ttuna/msot-redis,honestme/redis,Sciumo/redis,rouzier/redis,ketor/redis,xujunhai1991/redis,csuhawk/redis,drinkthere/redis-3.0-annotated,unasm/redis-3.0-annotated,darksideofthemoo/redis-histogram,kensou97/redis,HeartSaVioR/redis,gilala/hbjredis,ituncle/redis,HeartSaVioR/redis,jasonkying/redis,soveran/redis,hornen/redis,dreamquster/redis,GrimDerp/redis,valdsJohn/redis,tjschuck/redis,miaoyc1989/redis-3.0-annotated,a-pavlov/redis,OmarQunsul/graph-redis,gilala/bjredis,Aaron1992/redis,SyntaxStacks/redis,holstvoogd/redis,brg-liuwei/redis,oranagra/redis,izhoujie/redis,gilala/hbjredis,tjschuck/redis,ReadCode/redis-3.0-annotated,sunheehnus/redis,gilala/bjredis,HunanTV/redis,davidradunz/redis,xuzhezhaozhao/redis_reading,h0x91b/redis,alenslan/redis,guker/redis,cusspvz/redis,itugs/redis,wangyikai/redis,ramonsnir/redis,zy416548283/redis-3.0-annotated,AplayER/redis,ipmobiletech/redis,SummonY/redis,pcarrier/redis,Aliceljm1/redis-3.0-annotated,Hailei/redis,rogerchina/redis,izhoujie/redis,HouKangkang/redis-3.0-annotated,PKRoma/redis,sunheehnus/redis,huangz1990/redis-3.0-annotated,Aliceljm1/redis,rrsean/redis-3.0-annotated,cloudrain21/redis,jacklee0810/redis-3.0-annotated,jackyan/redis,mcanthony/redis,YuanZhewei/redis,yossigo/redis,mengyou0304/redis,j0hnma/szredis,netroby/redis,yuzhangjob/redis-3.0-annotated-unstable,vincent-vivian-liu/redis,tellapart/redis,nilyang/redis-tdd-annotation,xuguruogu/redis,YongMan/redis,jbochi/parallel_redis,valdsJohn/redis,clamoriniere1A/redis,saisai/redis,OmarQunsul/graph-redis,AALEKH/redis,ofirluzon/redis,sunheehnus/redis,buobao/redis-3.0-annotated,zhiliaoniu/redis,PradheepShrinivasan/redis,spearhead-ea/redis,saisai/redis,MasahikoSawada/redis,huangz1990/experiment-redis,xuguruogu/redis,splitice/redis,valdsJohn/redis,huangz1990/experiment-redis,jingjidejuren/redis,atreeyang/redis,neomantra/redis,fankeke/redis-3.0-annotated,davidradunz/redis,seandsky/redis,harrisonfeng/redis,modulexcite/redis,MasahikoSawada/redis,kaushik94/redis,nilyang/redis-tdd-annotation,supasate/redis,gongice/redis-3.0-annotated,oranagra/redis,badboy/redis,JoeWoo/redis,wbailey5/redis,devaos/redis,mengzhejin/RedisStudy,healerkx/redis,pmem/redis,shreesundara/redis,harrisonfeng/redis,msn217/redis-3.0-annotated,haima-zju/redis-3.0-annotated,yuhc/redis-benchmark-enhanced,z-fork/redis,yybirdcf/learn-redis,mengyou0304/redis,elkingtonmcb/redis,elkingtonmcb/redis,a-pavlov/redis,ofirluzon/redis,cusspvz/redis,weizijun/redis,MOON-CLJ/redis,haima-zju/redis-3.0-annotated,mumingv/redis,yossigo/redis,ttuna/msot-redis,wbailey5/redis,duanx/redis,alenslan/redis,spinlock/redis,roth1002/redis,kensou97/redis,blackmady/redis,tzq668766/redis-3.0-annotated,wenxueliu/redis_comment,zy416548283/redis-3.0-annotated,soveran/redis,kensou97/redis,cnbin/redis,0x55/redis-3.0-annotated,gilala/bjredis,pkdevbox/redis,roth1002/redis,mcanthony/redis,yossigo/redis,4396/redis,linfangrong/redis,csuhawk/redis,francischan714/redis,LongXQ/redis,janekmi/redis,tanghaodong25/redis,wujf/redis,zhoudayang/redis,AplayER/redis,antirez/redis,WorkingOfTimtohyZhang/redis-3.0-annotated,simplestbest/redis,Sciumo/redis,guker/redis,rogerlz/redis,gilala/hbjredis,himoca/redis,huangz1990/experiment-redis,PKRoma/redis,hgl888/redis,pedigree/redis,hawkchch/redis,saisai/redis,jingjidejuren/redis,Hailei/redis,jasonkying/redis,fengshao0907/redis,jackyan/redis,jingjidejuren/redis,whille/redis-3.0-annotated,nilyang/redis-tdd-annotation,tellapart/redis,honestme/redis,riyan8250/redis,mingyaaaa/redis,gaoxianglong/redis,whille/redis-3.0-annotated,thomasdarimont/redis,j0hnma/hszredis,universsky/redis,dreamquster/redis,antirez/redis,saisai/redis,huangz1990/redis-3.0-annotated,mumingv/redis-3.0-annotated,mgk/redis,colstrom/redis,itugs/redis,antirez/redis,MSOpenTech/redis,arijitvt/redis,GitHubMota/redis,pcarrier/redis,PradheepShrinivasan/redis,Aaron1992/redis,charsyam/redis,msn217/redis-3.0-annotated,Aliceljm1/redis,Soledad89/redis,WorkingOfTimtohyZhang/redis-3.0-annotated,wuyu201321060203/redis-3.0-annotated,josiahcarlson/redis,supasate/redis,yuhc/redis-benchmark-enhanced,ksarch-saas/redis,nnog/redis,wangyikai/redis,narma/redis,z-fork/redis,duanx/redis,RepmujNetsik/redis,magastzheng/redis-3.0-annotated,programmecat/redis,harrisonfeng/redis,allengaller/redis,charsyam/redis,Soledad89/redis,josiahcarlson/redis,wbailey5/redis,AALEKH/redis,h0x91b/redis,nnog/redis,drinkthere/redis-3.0-annotated,xlzhan/redis,YuraLukashik/redis,nuxeh/redis,YongMan/redis,wprice/redis,himoca/redis,dongqifan2/redis-3.0-annotated,RepmujNetsik/redis,idning/redis,universsky/redis,unasm/redis-3.0-annotated,wenxueliu/redis_comment,rogerlz/redis,dayuoba/redis,zczhuohuo/redis,citusdata/redis,ksarch-saas/redis,rouzier/redis,soloestoy/redis,ytjiang/redis,gilala/hredis,badboy/redis,HunanTV/redis,tellapart/redis,StevenTsai/redis,gilala/bjredis,xuzhezhaozhao/redis_reading,zguangyu/redis,h0x91b/redis,yuhc/redis-benchmark-enhanced,AALEKH/redis,SummonY/redis,blackmady/redis,RepmujNetsik/redis,arijitvt/redis,ErikDubbelboer/redis,rogerchina/redis,csuhawk/redis,honestme/redis,Hailei/redis,Aliceljm1/redis-3.0-annotated,honestme/redis,davidradunz/redis,dayuoba/redis,iandyh/redis,miaoyc1989/redis-3.0-annotated,MOON-CLJ/redis,wuyu201321060203/redis-3.0-annotated,timothyohare/3rdPartySrc-redis,wangyikai/redis,zhoudayang/redis,idning/redis,JoeWoo/redis,ttuna/msot-redis,tanghaodong25/redis,PradheepShrinivasan/redis,itamarhaber/redis,shining-yang/redis,flashbuckets/redis,cloudrain21/redis,roth1002/redis,july2993/redis,blackmady/redis,netroby/redis,jackyan/redis,cnbin/redis,seppo0010/rlite-server,ofirluzon/redis,slfs007/mk-redis,HunanTV/redis,itugs/redis,nuxeh/redis,francischan714/redis,valdsJohn/redis,mingyaaaa/redis,HunanTV/redis,shreesundara/redis,ytjiang/redis,NBSW/redis,shreesundara/redis,Wangyao14cyy/redis,0x55/redis-3.0-annotated,abhiklodh/redis,zhoudayang/redis,takeshineshiro/redis,devaos/redis,clamoriniere1A/redis,thomasdarimont/redis,Markgorden/redis,spinlock/redis,magastzheng/redis-3.0-annotated,kmiku7/redis,4396/redis,pedigree/redis,taoguan/redis,wenxueliu/redis_comment,thomasdarimont/redis,Sciumo/redis,yybirdcf/learn-redis,aim-for-better/redis,huyuezheng/redis,jacklee0810/redis-3.0-annotated,ctripcorp/redis,Aliceljm1/redis,kaushik94/redis,GrimDerp/redis,mcanthony/redis,rogerchina/redis,Markgorden/redis,PradheepShrinivasan/redis,mengzhejin/RedisStudy,hawkchch/redis,qiyang0221/redis,kmiku7/redis,wbailey5/redis,ramonsnir/redis,CodeJuan/redis,aim-for-better/redis,ofirluzon/redis,splitice/redis,onlymellb/redis-3.0-annotated,gechong/redis-3.0-annotated,ncopa/redis,HeartSaVioR/redis,NBSW/redis,SummonY/redis,taoguan/redis,gongice/redis-3.0-annotated,msn217/redis-3.0-annotated,ctripcorp/redis,dayuoba/redis,charsyam/redis,YuraLukashik/redis,zczhuohuo/redis,GrimDerp/redis,abhiklodh/redis,MasahikoSawada/redis,StevenTsai/redis,YuanZhewei/redis,YuanZhewei/redis,yuhc/redis-benchmark-enhanced,elkingtonmcb/redis,taoguan/redis,huangz1990/redis-3.0-annotated,louisliangjun/redis,gongice/redis-3.0-annotated,janekmi/redis,j0hnma/hszredis,xlzhan/redis,seppo0010/redis,jacklee0810/redis-3.0-annotated,mverrilli/redis