Trim residual complexity from server join notifications

Now that serf node join events are decoupled from rebalancing activities completely, remove the complixity of draining the channel and ensuring only one go routine was rebalancing the server list.

Now that we're no longer initializing a notification channel, we can remove the config load/save from `Start()`

consul/server_manager/server_manager.go

@@ -295,36 +295,13 @@ func (sm *ServerManager) refreshServerRebalanceTimer(timer *time.Timer) time.Dur
 // distribute load across all known and available consul servers.
 func (sm *ServerManager) Start() {
 	var rebalanceTimer *time.Timer = time.NewTimer(clientRPCMinReuseDuration)
-	var rebalanceTaskDispatched int32
-
-	func() {
-		sm.serverConfigLock.Lock()
-		defer sm.serverConfigLock.Unlock()
-
-		serverCfgPtr := sm.serverConfigValue.Load()
-		if serverCfgPtr == nil {
-			panic("server config has not been initialized")
-		}
-		var serverCfg serverConfig
-		serverCfg = serverCfgPtr.(serverConfig)
-		sm.saveServerConfig(serverCfg)
-	}()
 
 	for {
 		select {
 		case <-rebalanceTimer.C:
-			sm.logger.Printf("[INFO] server manager: server rebalance timeout")
+			sm.logger.Printf("[INFO] server manager: Rebalancing server connections")
 			sm.RebalanceServers()
-
-			// Only run one rebalance task at a time, but do
-			// allow for the channel to be drained
-			if atomic.CompareAndSwapInt32(&rebalanceTaskDispatched, 0, 1) {
-				sm.logger.Printf("[INFO] server manager: Launching rebalance duration task")
-				go func() {
-					defer atomic.StoreInt32(&rebalanceTaskDispatched, 0)
-					sm.refreshServerRebalanceTimer(rebalanceTimer)
-				}()
-			}
+			sm.refreshServerRebalanceTimer(rebalanceTimer)
 
 		case <-sm.shutdownCh:
 			sm.logger.Printf("[INFO] server manager: shutting down")