Document mostly dead code in RPOPLPUSH implementation.
Document mostly dead code in RPOPLPUSH implementation.

StartTheShift/redis-shift,janeasystems/redis,miminus/redis,liqiang199105/redis,kolonse/redis,laurencee/redis,quangnguyen90/redis,crask/redis-cutter,jqk6/redis,jqk6/redis,Cybermaxs/redis,Jonavin/redis,quangnguyen90/redis,alpha8/redis,enginekit/redis,jaambee/redis,grisha/thredis,powerumc/MyRedis,miminus/redis,alpha8/redis,grisha/thredis,Cybermaxs/redis,janeasystems/redis,nandhanurrevanth/redis,powerumc/MyRedis_old,LittlePeng/redis,shanegxxiao/redis,erwin00776/redis-2.8-optimize,Cybermaxs/redis,liqiang199105/redis,kolonse/redis,sidsen/redis,richmonkey/netleveldb,sidsen/redis,damy/redis,Jonavin/redis,Cybermaxs/redis,upsoft/redis,daogangtang/redis_luajit2.6,DeNA/redis,jacklee0810/redis,LittlePeng/redis,shanegxxiao/redis,daogangtang/redis_luajit2.6,erwin00776/redis-2.8-optimize,richmonkey/netleveldb,kolonse/redis,kts12345/redis,kts12345/redis,damy/redis,fanxu/redis,DeNA/redis,alpha8/redis,erwin00776/redis-2.8-optimize,janeasystems/redis,ideaar/redis,shanegxxiao/redis,upsoft/redis,ScottKaiGu/redis,jacklee0810/redis,erwin00776/redis-2.8-optimize,ideaar/redis,jqk6/redis,damy/redis,liqiang199105/redis,Cybermaxs/redis,LittlePeng/redis,fanxu/redis,powerumc/MyRedis,hanmichael/redis,DeNA/redis,powerumc/MyRedis_old,laurencee/redis,miminus/redis,quangnguyen90/redis,ScottKaiGu/redis,kts12345/redis,fanxu/redis,quangnguyen90/redis,daogangtang/redis_luajit2.6,richmonkey/netleveldb,jaambee/redis,grisha/thredis,fanxu/redis,jaambee/redis,nandhanurrevanth/redis,upsoft/redis,sidsen/redis,janeasystems/redis,sidsen/redis,janeasystems/redis,grisha/thredis,laurencee/redis,ideaar/redis,kts12345/redis,powerumc/MyRedis_old,miminus/redis,powerumc/MyRedis_old,laurencee/redis,crask/redis-cutter,hanmichael/redis,jacklee0810/redis,jqk6/redis,shanegxxiao/redis,ScottKaiGu/redis,nandhanurrevanth/redis,adamweixuan/redis,enginekit/redis,jaambee/redis,hanmichael/redis,laurencee/redis,ideaar/redis,jacklee0810/redis,richmonkey/netleveldb,oaastest/redis,ScottKaiGu/redis,daogangtang/redis_luajit2.6,ScottKaiGu/redis,powerumc/MyRedis,hanmichael/redis,StartTheShift/redis-shift,ideaar/redis,enginekit/redis,adamweixuan/redis,kolonse/redis,liqiang199105/redis,jacklee0810/redis,damy/redis,oaastest/redis,damy/redis,nandhanurrevanth/redis,sidsen/redis,enginekit/redis,Jonavin/redis,jqk6/redis,oaastest/redis,kts12345/redis,adamweixuan/redis,StartTheShift/redis-shift,shanegxxiao/redis,enginekit/redis,upsoft/redis,adamweixuan/redis,jaambee/redis,alpha8/redis,crask/redis-cutter,sidsen/redis,quangnguyen90/redis,oaastest/redis,Jonavin/redis,adamweixuan/redis,liqiang199105/redis,oaastest/redis,upsoft/redis,Jonavin/redis,alpha8/redis,hanmichael/redis,nandhanurrevanth/redis,kolonse/redis,miminus/redis