Merge pull request #5884 from chendq8/cluster_failover

Reduce 100ms of cluster failover time on Manual mode

src/cluster.c

@@ -3031,6 +3031,7 @@ void clusterHandleSlaveFailover(void) {
         if (server.cluster->mf_end) {
             server.cluster->failover_auth_time = mstime();
             server.cluster->failover_auth_rank = 0;
+	    clusterDoBeforeSleep(CLUSTER_TODO_HANDLE_FAILOVER);
         }
         serverLog(LL_WARNING,
             "Start of election delayed for %lld milliseconds "