Sentinel: slaves reconfig delay modified.

The time Sentinel waits since the slave is detected to be configured to
the wrong master, before reconfiguring it, is now the failover_timeout
time as this makes more sense in order to give the Sentinel performing
the failover enoung time to reconfigure the slaves slowly (if required
by the configuration).

Also we now PUBLISH more frequently the new configuraiton as this allows
to switch the reapprearing master back to slave faster.

src/sentinel.c

@@ -77,7 +77,7 @@ typedef struct sentinelAddr {
 #define SENTINEL_INFO_PERIOD 10000
 #define SENTINEL_PING_PERIOD 1000
 #define SENTINEL_ASK_PERIOD 1000
-#define SENTINEL_PUBLISH_PERIOD 5000
+#define SENTINEL_PUBLISH_PERIOD 2000
 #define SENTINEL_DOWN_AFTER_PERIOD 30000
 #define SENTINEL_HELLO_CHANNEL "__sentinel__:hello"
 #define SENTINEL_TILT_TRIGGER 2000
@@ -1650,7 +1650,7 @@ void sentinelRefreshInstanceInfo(sentinelRedisInstance *ri, const char *info) {
         (ri->slave_master_port != ri->master->addr->port ||
          strcasecmp(ri->slave_master_host,ri->master->addr->ip)))
     {
-        mstime_t wait_time = SENTINEL_PUBLISH_PERIOD*4;
+        mstime_t wait_time = ri->master->failover_timeout;
 
         /* Make sure the master is sane before reconfiguring this instance
          * into a slave. */