Cluster: more robust slave check in CLUSTER REPLICATE.
Cluster: more robust slave check in CLUSTER REPLICATE.

There are rare conditions where node->slaveof may be NULL even if the
node is a slave. To check by flag is much more robust.

pkdevbox/redis,yossigo/redis,rogerchina/redis,zhcy/redis,kensou97/redis,netroby/redis,wprice/redis,clamoriniere1A/redis,taoguan/redis,spinlock/redis,zczhuohuo/redis,ncopa/redis,wbailey5/redis,simplestbest/redis,antirez/redis,saisai/redis,pedigree/redis,davidradunz/redis,oranagra/redis,a-pavlov/redis,izhoujie/redis,gaoxianglong/redis,holstvoogd/redis,SummonY/redis,Sciumo/redis,MasahikoSawada/redis,hgl888/redis,MasahikoSawada/redis,charsyam/redis,ErikDubbelboer/redis,PradheepShrinivasan/redis,zczhuohuo/redis,Wangyao14cyy/redis,vincent-vivian-liu/redis,shreesundara/redis,Soledad89/redis,huyuezheng/redis,YuraLukashik/redis,gaoxianglong/redis,saisai/redis,JoeWoo/redis,antirez/redis,yuhc/redis-benchmark-enhanced,badboy/redis,Soledad89/redis,wprice/redis,kmiku7/redis,zhcy/redis,wangyikai/redis,h0x91b/redis,weizijun/redis,rouzier/redis,twskipper/redis,ton31337/redis,ouyangkongtong/redis,izhoujie/redis,july2993/redis,seandsky/redis,SyntaxStacks/redis,NBSW/redis,seandsky/redis,dreamquster/redis,tanghaodong25/redis,AALEKH/redis,guker/redis,SyntaxStacks/redis,july2993/redis,blackmady/redis,hornen/redis,StevenTsai/redis,valdsJohn/redis,ErikDubbelboer/redis,mgk/redis,honestme/redis,brg-liuwei/redis,Markgorden/redis,jackyan/redis,thomasdarimont/redis,holstvoogd/redis,supasate/redis,pcarrier/redis,LongXQ/redis,wprice/redis,rouzier/redis,rogerlz/redis,davidradunz/redis,hedisdb/hedis,mengyou0304/redis,kaushik94/redis,dreamquster/redis,sunheehnus/redis,programmecat/redis,YuraLukashik/redis,dreamquster/redis,LongXQ/redis,PKRoma/redis,devaos/redis,SummonY/redis,alenslan/redis,flashbuckets/redis,shining-yang/redis,linfangrong/redis,takeshineshiro/redis,harrisonfeng/redis,elkingtonmcb/redis,huyuezheng/redis,nuxeh/redis,fengshao0907/redis,modulexcite/redis,fengshao0907/redis,rogerchina/redis,ytjiang/redis,spinlock/redis,fengshao0907/redis,francischan714/redis,harrisonfeng/redis,hedisdb/hedis,spinlock/redis,dayuoba/redis,tanghaodong25/redis,itugs/redis,JoeWoo/redis,ErikDubbelboer/redis,mcanthony/redis,Markgorden/redis,MasahikoSawada/redis,twskipper/redis,citusdata/redis,wbailey5/redis,cusspvz/redis,davidradunz/redis,AplayER/redis,shreesundara/redis,seppo0010/redis,csuhawk/redis,atreeyang/redis,universsky/redis,YuanZhewei/redis,pmem/redis,soveran/redis,rogerlz/redis,taoguan/redis,jingjidejuren/redis,mverrilli/redis,qiyang0221/redis,h0x91b/redis,Sciumo/redis,wenxueliu/redis_comment,SyntaxStacks/redis,healerkx/redis,itamarhaber/redis,netroby/redis,ituncle/redis,a-pavlov/redis,csuhawk/redis,hedisdb/hedis,kensou97/redis,xuguruogu/redis,rogerlz/redis,zhiliaoniu/redis,itamarhaber/redis,ipmobiletech/redis,wangyikai/redis,PKRoma/redis,zguangyu/redis,seppo0010/redis,seandsky/redis,tanghaodong25/redis,zczhuohuo/redis,mverrilli/redis,universsky/redis,GitHubMota/redis,cusspvz/redis,simplestbest/redis,jackyan/redis,abhiklodh/redis,oranagra/redis,ncopa/redis,OmarQunsul/graph-redis,allengaller/redis,mumingv/redis,NBSW/redis,h0x91b/redis,jingjidejuren/redis,elkingtonmcb/redis,harrisonfeng/redis,Aliceljm1/redis,zhiliaoniu/redis,riyan8250/redis,atreeyang/redis,pcarrier/redis,universsky/redis,mcanthony/redis,blackmady/redis,pmem/redis,ipmobiletech/redis,csuhawk/redis,GrimDerp/redis,roth1002/redis,janekmi/redis,ofirluzon/redis,rogerchina/redis,dayuoba/redis,tjschuck/redis,seppo0010/redis,ErikDubbelboer/redis,4396/redis,pedigree/redis,z-fork/redis,ctripcorp/redis,jackyan/redis,yuhc/redis-benchmark-enhanced,modulexcite/redis,soloestoy/redis,ituncle/redis,ton31337/redis,iandyh/redis,tjschuck/redis,AALEKH/redis,guker/redis,allengaller/redis,blackmady/redis,cloudrain21/redis,nnog/redis,itugs/redis,holstvoogd/redis,harrisonfeng/redis,neomantra/redis,wenxueliu/redis_comment,Aliceljm1/redis,izhoujie/redis,holstvoogd/redis,seandsky/redis,yossigo/redis,roth1002/redis,xujunhai1991/redis,healerkx/redis,francischan714/redis,AplayER/redis,duanx/redis,aim-for-better/redis,itugs/redis,wenxueliu/redis_comment,ouyangkongtong/redis,honestme/redis,ofirluzon/redis,flashbuckets/redis,flashbuckets/redis,oranagra/redis,francischan714/redis,z-fork/redis,colstrom/redis,pedigree/redis,july2993/redis,zguangyu/redis,janekmi/redis,LongXQ/redis,4396/redis,ytjiang/redis,yuhc/redis-benchmark-enhanced,Wangyao14cyy/redis,ipmobiletech/redis,healerkx/redis,ituncle/redis,antirez/redis,StevenTsai/redis,NBSW/redis,CodeJuan/redis,wprice/redis,mingyaaaa/redis,Sciumo/redis,seppo0010/redis,SummonY/redis,kmiku7/redis,yossigo/redis,OmarQunsul/graph-redis,ouyangkongtong/redis,badboy/redis,valdsJohn/redis,PradheepShrinivasan/redis,hawkchch/redis,csuhawk/redis,Sciumo/redis,ipmobiletech/redis,YuanZhewei/redis,zguangyu/redis,ofirluzon/redis,blackmady/redis,arijitvt/redis,Wangyao14cyy/redis,clamoriniere1A/redis,alenslan/redis,soloestoy/redis,4396/redis,ctripcorp/redis,alenslan/redis,hedisdb/hedis,aim-for-better/redis,francischan714/redis,riyan8250/redis,modulexcite/redis,mingyaaaa/redis,cloudrain21/redis,citusdata/redis,cnbin/redis,brg-liuwei/redis,Soledad89/redis,mverrilli/redis,pedigree/redis,riyan8250/redis,kaushik94/redis,SyntaxStacks/redis,zhcy/redis,nuxeh/redis,xlzhan/redis,dreamquster/redis,valdsJohn/redis,yossigo/redis,190235047/redis,saisai/redis,mengyou0304/redis,z-fork/redis,izhoujie/redis,OmarQunsul/graph-redis,cloudrain21/redis,takeshineshiro/redis,xlzhan/redis,AplayER/redis,xuguruogu/redis,mgk/redis,YongMan/redis,xlzhan/redis,PKRoma/redis,vincent-vivian-liu/redis,supasate/redis,4396/redis,allengaller/redis,GitHubMota/redis,twskipper/redis,davidradunz/redis,YuraLukashik/redis,xujunhai1991/redis,sunheehnus/redis,devaos/redis,StevenTsai/redis,charsyam/redis,elkingtonmcb/redis,190235047/redis,wbailey5/redis,vincent-vivian-liu/redis,shining-yang/redis,hornen/redis,pcarrier/redis,colstrom/redis,a-pavlov/redis,simplestbest/redis,hawkchch/redis,july2993/redis,kaushik94/redis,iandyh/redis,honestme/redis,thomasdarimont/redis,tjschuck/redis,alenslan/redis,guker/redis,Markgorden/redis,atreeyang/redis,soveran/redis,ytjiang/redis,GrimDerp/redis,charsyam/redis,soveran/redis,huyuezheng/redis,soveran/redis,thomasdarimont/redis,wangyikai/redis,abhiklodh/redis,zguangyu/redis,duanx/redis,nnog/redis,jingjidejuren/redis,badboy/redis,GrimDerp/redis,charsyam/redis,brg-liuwei/redis,modulexcite/redis,itugs/redis,clamoriniere1A/redis,mumingv/redis,rouzier/redis,supasate/redis,twskipper/redis,netroby/redis,hornen/redis,huyuezheng/redis,neomantra/redis,jingjidejuren/redis,linfangrong/redis,StevenTsai/redis,kensou97/redis,CodeJuan/redis,ofirluzon/redis,cnbin/redis,kaushik94/redis,netroby/redis,PKRoma/redis,tjschuck/redis,mingyaaaa/redis,hgl888/redis,hawkchch/redis,vincent-vivian-liu/redis,YongMan/redis,mengyou0304/redis,cusspvz/redis,badboy/redis,mingyaaaa/redis,saisai/redis,GrimDerp/redis,hawkchch/redis,qiyang0221/redis,cnbin/redis,pkdevbox/redis,AplayER/redis,iandyh/redis,weizijun/redis,ytjiang/redis,gaoxianglong/redis,guker/redis,charsyam/redis,Markgorden/redis,wangyikai/redis,wenxueliu/redis_comment,janekmi/redis,citusdata/redis,ouyangkongtong/redis,zczhuohuo/redis,citusdata/redis,shreesundara/redis,taoguan/redis,JoeWoo/redis,Soledad89/redis,PradheepShrinivasan/redis,programmecat/redis,devaos/redis,oranagra/redis,abhiklodh/redis,fengshao0907/redis,shining-yang/redis,spinlock/redis,arijitvt/redis,YongMan/redis,AALEKH/redis,JoeWoo/redis,thomasdarimont/redis,tellapart/redis,clamoriniere1A/redis,weizijun/redis,dayuoba/redis,atreeyang/redis,MasahikoSawada/redis,Aliceljm1/redis,soloestoy/redis,Wangyao14cyy/redis,roth1002/redis,flashbuckets/redis,nuxeh/redis,AALEKH/redis,yuhc/redis-benchmark-enhanced,zhiliaoniu/redis,NBSW/redis,duanx/redis,GitHubMota/redis,oranagra/redis,xujunhai1991/redis,ncopa/redis,mengyou0304/redis,YuanZhewei/redis,CodeJuan/redis,sunheehnus/redis,YuanZhewei/redis,soloestoy/redis,linfangrong/redis,programmecat/redis,neomantra/redis,rogerlz/redis,simplestbest/redis,wbailey5/redis,pmem/redis,allengaller/redis,mumingv/redis,190235047/redis,shining-yang/redis,hgl888/redis,ncopa/redis,antirez/redis,kmiku7/redis,mgk/redis,hgl888/redis,soloestoy/redis,OmarQunsul/graph-redis,gaoxianglong/redis,colstrom/redis,zhcy/redis,PradheepShrinivasan/redis,jackyan/redis,YongMan/redis,healerkx/redis,weizijun/redis,cnbin/redis,xujunhai1991/redis,SummonY/redis,tellapart/redis,rouzier/redis,aim-for-better/redis,kmiku7/redis,elkingtonmcb/redis,190235047/redis,nnog/redis,qiyang0221/redis,z-fork/redis,pkdevbox/redis,nuxeh/redis,programmecat/redis,mcanthony/redis,duanx/redis,linfangrong/redis,ctripcorp/redis,neomantra/redis,xuguruogu/redis,mcanthony/redis,cloudrain21/redis,roth1002/redis,kensou97/redis,xuguruogu/redis,tellapart/redis,GitHubMota/redis,zhiliaoniu/redis,valdsJohn/redis,arijitvt/redis,ton31337/redis,itamarhaber/redis,taoguan/redis,shreesundara/redis,cusspvz/redis,ctripcorp/redis,dayuoba/redis,mumingv/redis,CodeJuan/redis,PKRoma/redis,ton31337/redis,supasate/redis,devaos/redis,tellapart/redis,LongXQ/redis,aim-for-better/redis,mverrilli/redis,qiyang0221/redis,neomantra/redis,iandyh/redis,tanghaodong25/redis,takeshineshiro/redis,takeshineshiro/redis,abhiklodh/redis,rogerchina/redis,pmem/redis,hornen/redis,YuraLukashik/redis,Aliceljm1/redis,a-pavlov/redis,riyan8250/redis,h0x91b/redis,honestme/redis,pkdevbox/redis,mgk/redis,yossigo/redis,sunheehnus/redis,janekmi/redis,colstrom/redis,universsky/redis,ofirluzon/redis,itamarhaber/redis,xlzhan/redis,brg-liuwei/redis,pcarrier/redis,ituncle/redis,nnog/redis,arijitvt/redis