Sentinel: add Redis execution mode to INFO output.
Sentinel: add Redis execution mode to INFO output.

The new "redis_mode" field in the INFO output will show if Redis is
running in standalone mode, cluster, or sentinel mode.

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