Fix NPE when getting the localhost using admin tool (#518)

tools/src/main/java/org/apache/rocketmq/tools/admin/DefaultMQAdminExtImpl.java

@@ -842,7 +842,7 @@ public class DefaultMQAdminExtImpl implements MQAdminExt, MQAdminExtInner {
                 BrokerData brokerData = ci.getBrokerAddrTable().get(mq.getBrokerName());
                 if (brokerData != null) {
                     String addr = brokerData.getBrokerAddrs().get(MixAll.MASTER_ID);
-                    if (addr.equals(RemotingUtil.socketAddress2String(msg.getStoreHost()))) {
+                    if (RemotingUtil.socketAddress2String(msg.getStoreHost()).equals(addr)) {
                         if (next.getValue().getConsumerOffset() > msg.getQueueOffset()) {
                             return true;
                         }