Merge pull request #2043 from wqliang/selectNamesrv

[ISSUE #2042]select a new namesrv when the old one removed from namesrvAddrList

remoting/src/main/java/org/apache/rocketmq/remoting/netty/NettyRemotingClient.java

@@ -354,6 +354,10 @@ public class NettyRemotingClient extends NettyRemotingAbstract implements Remoti
                 Collections.shuffle(addrs);
                 log.info("name server address updated. NEW : {} , OLD: {}", addrs, old);
                 this.namesrvAddrList.set(addrs);
+
+                if (!addrs.contains(this.namesrvAddrChoosed.get())) {
+                    this.namesrvAddrChoosed.set(null);
+                }
             }
         }
     }