Cluster: configEpoch collisions resolution.
Cluster: configEpoch collisions resolution.

The slave election in Redis Cluster guarantees that slaves promoted to
masters always end with unique config epochs, however failures during
manual reshardings, software bugs and operational errors may in theory
cause two nodes to have the same configEpoch.

This commit introduces a mechanism to eventually always end with different
configEpochs if a collision ever happens.

As a (wanted) side effect, this also ensures that after a new cluster
is created, all nodes will end with a different configEpoch automatically.

tanghaodong25/redis,hawkchch/redis,GrimDerp/redis,shreesundara/redis,kmiku7/redis,csuhawk/redis,ituncle/redis,gilala/bjredis,narma/redis,seppo0010/redis,healerkx/redis,hedisdb/hedis,j0hnma/szredis,antirez/redis,mingyaaaa/redis,rogerchina/redis,colstrom/redis,MasahikoSawada/redis,kaushik94/redis,clamoriniere1A/redis,wenxueliu/redis_comment,gaoxianglong/redis,gilala/hredis,supasate/redis,GitHubMota/redis,gilala/hredis,iandyh/redis,twskipper/redis,flashbuckets/redis,ipmobiletech/redis,gilala/redis,riyan8250/redis,tjschuck/redis,cnbin/redis,seppo0010/rlite-server,oranagra/redis,davidradunz/redis,pkdevbox/redis,taoguan/redis,atreeyang/redis,Aliceljm1/redis,flashbuckets/redis,zguangyu/redis,z-fork/redis,neomantra/redis,kmiku7/redis,itugs/redis,supasate/redis,gaoxianglong/redis,mgk/redis,SummonY/redis,gilala/hredis,sunheehnus/redis,ErikDubbelboer/redis,JoeWoo/redis,CodeJuan/redis,mumingv/redis,zczhuohuo/redis,ton31337/redis,thomasdarimont/redis,july2993/redis,wenxueliu/redis_comment,jbochi/redis,riyan8250/redis,badboy/redis,seppo0010/rlite-server,alenslan/redis,LongXQ/redis,tjschuck/redis,ouyangkongtong/redis,gilala/hbjredis,kmiku7/redis,YuraLukashik/redis,xuguruogu/redis,mverrilli/redis,gilala/bjredis,wenxueliu/redis_comment,nnog/redis,jasonkying/redis,itamarhaber/redis,devaos/redis,jasonkying/redis,supasate/redis,YongMan/redis,izhoujie/redis,oranagra/redis,duanx/redis,hawkchch/redis,gilala/hbjredis,universsky/redis,abhiklodh/redis,Sciumo/redis,nnog/redis,antirez/redis,AplayER/redis,atreeyang/redis,simplestbest/redis,wprice/redis,takeshineshiro/redis,linfangrong/redis,zhcy/redis,JoeWoo/redis,Soledad89/redis,yuhc/redis-benchmark-enhanced,hornen/redis,hornen/redis,huyuezheng/redis,yuhc/redis-benchmark-enhanced,pcarrier/redis,citusdata/redis,wangyikai/redis,nuxeh/redis,aim-for-better/redis,MasahikoSawada/redis,soveran/redis,zhcy/redis,mengyou0304/redis,timothyohare/3rdPartySrc-redis,kensou97/redis,rogerchina/redis,davidradunz/redis,zhiliaoniu/redis,dayuoba/redis,h0x91b/redis,jingjidejuren/redis,soloestoy/redis,harrisonfeng/redis,universsky/redis,weizijun/redis,shining-yang/redis,healerkx/redis,OmarQunsul/graph-redis,xuguruogu/redis,Wangyao14cyy/redis,seppo0010/rlite-server,arijitvt/redis,tanghaodong25/redis,PKRoma/redis,Sciumo/redis,Sciumo/redis,tellapart/redis,mattsta/redis,YuraLukashik/redis,linfangrong/redis,PKRoma/redis,healerkx/redis,ipmobiletech/redis,modulexcite/redis,jasonkying/redis,gilala/redis,citusdata/redis,elkingtonmcb/redis,alenslan/redis,4396/redis,csuhawk/redis,wujf/redis,modulexcite/redis,colstrom/redis,SyntaxStacks/redis,wangyikai/redis,cusspvz/redis,Markgorden/redis,izhoujie/redis,mingyaaaa/redis,soloestoy/redis,mcanthony/redis,LongXQ/redis,mengzhejin/RedisStudy,seppo0010/redis,ErikDubbelboer/redis,PradheepShrinivasan/redis,qiyang0221/redis,gaoxianglong/redis,h0x91b/redis,190235047/redis,ytjiang/redis,xlzhan/redis,davidradunz/redis,RepmujNetsik/redis,wenxueliu/redis_comment,weizijun/redis,xlzhan/redis,tanghaodong25/redis,dreamquster/redis,valdsJohn/redis,PradheepShrinivasan/redis,j0hnma/szredis,CodeJuan/redis,ituncle/redis,kensou97/redis,h0x91b/redis,StevenTsai/redis,shreesundara/redis,pedigree/redis,aim-for-better/redis,hawkchch/redis,190235047/redis,PKRoma/redis,zguangyu/redis,abhiklodh/redis,vincent-vivian-liu/redis,Wangyao14cyy/redis,neomantra/redis,saisai/redis,jbochi/parallel_redis,ctripcorp/redis,twskipper/redis,mengyou0304/redis,cusspvz/redis,pkdevbox/redis,Markgorden/redis,fengshao0907/redis,JoeWoo/redis,shining-yang/redis,tellapart/redis,badboy/redis,brg-liuwei/redis,yuhc/redis-benchmark-enhanced,rouzier/redis,duanx/redis,pedigree/redis,wangyikai/redis,wbailey5/redis,pcarrier/redis,ituncle/redis,xlzhan/redis,devaos/redis,YongMan/redis,takeshineshiro/redis,tjschuck/redis,fengshao0907/redis,ipmobiletech/redis,netroby/redis,yossigo/redis,vincent-vivian-liu/redis,seppo0010/redis,wujf/redis,thomasdarimont/redis,OmarQunsul/graph-redis,j0hnma/hszredis,ofirluzon/redis,jingjidejuren/redis,holstvoogd/redis,StevenTsai/redis,programmecat/redis,a-pavlov/redis,blackmady/redis,xuguruogu/redis,ctripcorp/redis,zhiliaoniu/redis,StevenTsai/redis,kensou97/redis,z-fork/redis,hornen/redis,twskipper/redis,jackyan/redis,mengyou0304/redis,Soledad89/redis,mumingv/redis,flashbuckets/redis,izhoujie/redis,taoguan/redis,citusdata/redis,nnog/redis,duanx/redis,colstrom/redis,jackyan/redis,harrisonfeng/redis,pcarrier/redis,NBSW/redis,elkingtonmcb/redis,wprice/redis,itamarhaber/redis,yuhc/redis-benchmark-enhanced,HeartSaVioR/redis,huyuezheng/redis,saisai/redis,ton31337/redis,holstvoogd/redis,wbailey5/redis,YuanZhewei/redis,linfangrong/redis,soveran/redis,zguangyu/redis,GitHubMota/redis,hawkchch/redis,honestme/redis,SyntaxStacks/redis,GitHubMota/redis,Markgorden/redis,j0hnma/szredis,oranagra/redis,vincent-vivian-liu/redis,brg-liuwei/redis,PKRoma/redis,roth1002/redis,mgk/redis,YongMan/redis,a-pavlov/redis,allengaller/redis,j0hnma/hszredis,takeshineshiro/redis,neomantra/redis,seandsky/redis,programmecat/redis,GrimDerp/redis,charsyam/redis,brg-liuwei/redis,july2993/redis,twskipper/redis,zhiliaoniu/redis,ErikDubbelboer/redis,arijitvt/redis,mverrilli/redis,rouzier/redis,HeartSaVioR/redis,sunheehnus/redis,jbochi/parallel_redis,qiyang0221/redis,guker/redis,rogerlz/redis,citusdata/redis,clamoriniere1A/redis,Markgorden/redis,OmarQunsul/graph-redis,iandyh/redis,Sciumo/redis,jbochi/parallel_redis,cnbin/redis,arijitvt/redis,jasonkying/redis,Aaron1992/redis,hgl888/redis,shining-yang/redis,Aliceljm1/redis,simplestbest/redis,antirez/redis,ErikDubbelboer/redis,narma/redis,universsky/redis,jbochi/redis,pmem/redis,francischan714/redis,wangyikai/redis,healerkx/redis,z-fork/redis,iandyh/redis,ipmobiletech/redis,a-pavlov/redis,sunheehnus/redis,clamoriniere1A/redis,ituncle/redis,HeartSaVioR/redis,hgl888/redis,aim-for-better/redis,MasahikoSawada/redis,elkingtonmcb/redis,dreamquster/redis,gilala/bjredis,roth1002/redis,antirez/redis,ncopa/redis,timothyohare/3rdPartySrc-redis,atreeyang/redis,ofirluzon/redis,Wangyao14cyy/redis,soveran/redis,mattsta/redis,duanx/redis,riyan8250/redis,tanghaodong25/redis,fengshao0907/redis,wujf/redis,dayuoba/redis,jbochi/redis,netroby/redis,universsky/redis,cnbin/redis,cloudrain21/redis,cusspvz/redis,AALEKH/redis,soloestoy/redis,4396/redis,weizijun/redis,gilala/hredis,mgk/redis,pmem/redis,SummonY/redis,NBSW/redis,hgl888/redis,fengshao0907/redis,Wangyao14cyy/redis,ctripcorp/redis,ton31337/redis,GrimDerp/redis,pmem/redis,guker/redis,josiahcarlson/redis,charsyam/redis,huyuezheng/redis,ncopa/redis,alenslan/redis,cloudrain21/redis,MOON-CLJ/redis,neomantra/redis,arijitvt/redis,YuanZhewei/redis,hornen/redis,davidradunz/redis,RepmujNetsik/redis,NBSW/redis,YuraLukashik/redis,z-fork/redis,charsyam/redis,mengzhejin/RedisStudy,colstrom/redis,SyntaxStacks/redis,programmecat/redis,honestme/redis,OmarQunsul/graph-redis,YuraLukashik/redis,guker/redis,josiahcarlson/redis,timothyohare/3rdPartySrc-redis,gilala/redis,Aaron1992/redis,seandsky/redis,seppo0010/rlite-server,YongMan/redis,netroby/redis,LongXQ/redis,huyuezheng/redis,hedisdb/hedis,xujunhai1991/redis,jackyan/redis,cnbin/redis,mumingv/redis,MOON-CLJ/redis,YuanZhewei/redis,charsyam/redis,4396/redis,hedisdb/hedis,hedisdb/hedis,Aaron1992/redis,j0hnma/szredis,cloudrain21/redis,tjschuck/redis,flashbuckets/redis,yossigo/redis,rogerchina/redis,seandsky/redis,guker/redis,StevenTsai/redis,thomasdarimont/redis,gilala/bjredis,ctripcorp/redis,kaushik94/redis,ofirluzon/redis,seppo0010/redis,h0x91b/redis,kaushik94/redis,dayuoba/redis,blackmady/redis,shining-yang/redis,kmiku7/redis,francischan714/redis,PradheepShrinivasan/redis,josiahcarlson/redis,vincent-vivian-liu/redis,rogerlz/redis,simplestbest/redis,taoguan/redis,dreamquster/redis,elkingtonmcb/redis,cusspvz/redis,charsyam/redis,jingjidejuren/redis,blackmady/redis,j0hnma/hszredis,qiyang0221/redis,aim-for-better/redis,honestme/redis,YuanZhewei/redis,jingjidejuren/redis,pedigree/redis,zhcy/redis,itugs/redis,pkdevbox/redis,valdsJohn/redis,jackyan/redis,nuxeh/redis,GrimDerp/redis,atreeyang/redis,mengyou0304/redis,mengzhejin/RedisStudy,honestme/redis,wujf/redis,qiyang0221/redis,RepmujNetsik/redis,ouyangkongtong/redis,spinlock/redis,CodeJuan/redis,mverrilli/redis,gilala/hbjredis,dreamquster/redis,Soledad89/redis,dayuoba/redis,spinlock/redis,rogerchina/redis,ncopa/redis,mattsta/redis,takeshineshiro/redis,harrisonfeng/redis,csuhawk/redis,yossigo/redis,soloestoy/redis,ouyangkongtong/redis,mumingv/redis,ofirluzon/redis,nuxeh/redis,j0hnma/hszredis,badboy/redis,modulexcite/redis,josiahcarlson/redis,xujunhai1991/redis,zczhuohuo/redis,oranagra/redis,saisai/redis,a-pavlov/redis,tellapart/redis,netroby/redis,itamarhaber/redis,roth1002/redis,gaoxianglong/redis,rogerlz/redis,RepmujNetsik/redis,narma/redis,francischan714/redis,JoeWoo/redis,july2993/redis,holstvoogd/redis,brg-liuwei/redis,gilala/redis,neomantra/redis,devaos/redis,pkdevbox/redis,rouzier/redis,valdsJohn/redis,mingyaaaa/redis,AALEKH/redis,mcanthony/redis,taoguan/redis,xlzhan/redis,clamoriniere1A/redis,190235047/redis,tellapart/redis,soloestoy/redis,riyan8250/redis,yossigo/redis,valdsJohn/redis,Aliceljm1/redis,janekmi/redis,MasahikoSawada/redis,harrisonfeng/redis,janekmi/redis,supasate/redis,pcarrier/redis,kensou97/redis,xujunhai1991/redis,NBSW/redis,hgl888/redis,4396/redis,ouyangkongtong/redis,AplayER/redis,janekmi/redis,wprice/redis,simplestbest/redis,PradheepShrinivasan/redis,mgk/redis,iandyh/redis,itugs/redis,CodeJuan/redis,csuhawk/redis,HeartSaVioR/redis,rouzier/redis,modulexcite/redis,allengaller/redis,soveran/redis,timothyohare/3rdPartySrc-redis,blackmady/redis,roth1002/redis,Aaron1992/redis,nuxeh/redis,sunheehnus/redis,oranagra/redis,AALEKH/redis,spinlock/redis,pedigree/redis,francischan714/redis,ton31337/redis,cloudrain21/redis,nnog/redis,allengaller/redis,wbailey5/redis,spinlock/redis,wbailey5/redis,janekmi/redis,LongXQ/redis,rogerlz/redis,190235047/redis,SummonY/redis,alenslan/redis,zhiliaoniu/redis,abhiklodh/redis,Soledad89/redis,GitHubMota/redis,xuguruogu/redis,kaushik94/redis,AplayER/redis,SyntaxStacks/redis,izhoujie/redis,saisai/redis,weizijun/redis,gilala/hbjredis,zhcy/redis,yossigo/redis,zczhuohuo/redis,ofirluzon/redis,linfangrong/redis,ncopa/redis,ytjiang/redis,zczhuohuo/redis,SummonY/redis,programmecat/redis,AALEKH/redis,itamarhaber/redis,holstvoogd/redis,PKRoma/redis,pmem/redis,shreesundara/redis,wprice/redis,Aliceljm1/redis,MOON-CLJ/redis,xujunhai1991/redis,july2993/redis,abhiklodh/redis,devaos/redis,ytjiang/redis,shreesundara/redis,seandsky/redis,mcanthony/redis,badboy/redis,mingyaaaa/redis,itugs/redis,zguangyu/redis,allengaller/redis,thomasdarimont/redis,mengzhejin/RedisStudy,mverrilli/redis,ytjiang/redis,mcanthony/redis,AplayER/redis