Sentinel: send hello messages ASAP after config change.
Sentinel: send hello messages ASAP after config change.

Eventual configuration convergence is guaranteed by our periodic hello
messages to all the instances, however when there are important notices
to share, better make a phone call. With this commit we force an hello
message to other Sentinal and Redis instances within the next 100
milliseconds of a config update, which is practically better than
waiting a few seconds.

damy/redis,sidsen/redis,sidsen/redis,shanegxxiao/redis,nandhanurrevanth/redis,hanmichael/redis,Cybermaxs/redis,hanmichael/redis,kolonse/redis,LittlePeng/redis,liqiang199105/redis,miminus/redis,enginekit/redis,damy/redis,ScottKaiGu/redis,Cybermaxs/redis,jacklee0810/redis,jaambee/redis,StartTheShift/redis-shift,kolonse/redis,shanegxxiao/redis,kolonse/redis,nandhanurrevanth/redis,quangnguyen90/redis,erwin00776/redis-2.8-optimize,ScottKaiGu/redis,enginekit/redis,sidsen/redis,Cybermaxs/redis,fanxu/redis,erwin00776/redis-2.8-optimize,jqk6/redis,upsoft/redis,Jonavin/redis,ideaar/redis,jaambee/redis,janeasystems/redis,shanegxxiao/redis,janeasystems/redis,shanegxxiao/redis,fanxu/redis,jacklee0810/redis,jaambee/redis,laurencee/redis,alpha8/redis,ScottKaiGu/redis,ScottKaiGu/redis,ideaar/redis,laurencee/redis,kts12345/redis,StartTheShift/redis-shift,sidsen/redis,upsoft/redis,laurencee/redis,janeasystems/redis,fanxu/redis,nandhanurrevanth/redis,jaambee/redis,damy/redis,kts12345/redis,enginekit/redis,shanegxxiao/redis,laurencee/redis,jqk6/redis,kolonse/redis,erwin00776/redis-2.8-optimize,miminus/redis,quangnguyen90/redis,jqk6/redis,LittlePeng/redis,enginekit/redis,adamweixuan/redis,hanmichael/redis,nandhanurrevanth/redis,jqk6/redis,miminus/redis,quangnguyen90/redis,StartTheShift/redis-shift,jqk6/redis,miminus/redis,Jonavin/redis,alpha8/redis,adamweixuan/redis,adamweixuan/redis,alpha8/redis,janeasystems/redis,kts12345/redis,jacklee0810/redis,adamweixuan/redis,upsoft/redis,jaambee/redis,Jonavin/redis,quangnguyen90/redis,quangnguyen90/redis,liqiang199105/redis,Jonavin/redis,upsoft/redis,kts12345/redis,Cybermaxs/redis,enginekit/redis,ideaar/redis,jacklee0810/redis,liqiang199105/redis,sidsen/redis,upsoft/redis,liqiang199105/redis,janeasystems/redis,Jonavin/redis,nandhanurrevanth/redis,damy/redis,hanmichael/redis,ScottKaiGu/redis,erwin00776/redis-2.8-optimize,alpha8/redis,fanxu/redis,damy/redis,ideaar/redis,liqiang199105/redis,alpha8/redis,miminus/redis,kolonse/redis,LittlePeng/redis,kts12345/redis,sidsen/redis,ideaar/redis,adamweixuan/redis,hanmichael/redis,jacklee0810/redis,laurencee/redis,Cybermaxs/redis