fix the bug caused in HA cluster in consumer (#723)

diff --git a/consumer/push_consumer.go b/consumer/push_consumer.go
index 08a1048..66bf367 100644
--- a/consumer/push_consumer.go
+++ b/consumer/push_consumer.go
@@ -106,7 +106,7 @@
 	if err != nil {
 		return nil, err
 	}
-
+	dc.namesrv = dc.option.ClientOptions.Namesrv
 	p := &pushConsumer{
 		defaultConsumer: dc,
 		subscribedTopic: make(map[string]string, 0),