Sentinel: remove useless sentinelFlushConfig() call

To rewrite the config in the loop that adds slaves back after a master
reset, in order to handle switching to another master, is useless: it
just adds latency since there is an fsync call in the inner loop,
without providing any additional guarantee, but the contrary, since if
after the first loop iteration the server crashes we end with just a
single slave entry losing all the other informations.

It is wiser to rewrite the config at the end when the full new
state is configured.

src/sentinel.c

@@ -1269,10 +1269,7 @@ int sentinelResetMasterAndChangeAddress(sentinelRedisInstance *master, char *ip,
         slave = createSentinelRedisInstance(NULL,SRI_SLAVE,slaves[j]->ip,
                     slaves[j]->port, master->quorum, master);
         releaseSentinelAddr(slaves[j]);
-        if (slave) {
-            sentinelEvent(REDIS_NOTICE,"+slave",slave,"%@");
-            sentinelFlushConfig();
-        }
+        if (slave) sentinelEvent(REDIS_NOTICE,"+slave",slave,"%@");
     }
     zfree(slaves);