Merge pull request #1129 from jack15083/1.5

fix panic: sync: negative WaitGroup counter
diff --git a/registry/zookeeper/registry.go b/registry/zookeeper/registry.go
index bef0ae5..12c78d9 100644
--- a/registry/zookeeper/registry.go
+++ b/registry/zookeeper/registry.go
@@ -79,6 +79,7 @@
 		return nil, err
 	}
 
+	r.WaitGroup().Add(1) //zk client start successful, then wg +1
 	go zookeeper.HandleClientRestart(r)
 
 	r.listener = zookeeper.NewZkEventListener(r.client)