Merge branch 'stable-2.13' into stable-2.14

* stable-2.13:
  Do not show update bar when there are no new messages

Change-Id: I580552817db4ae49ec6addd3ddef2b446644b715

gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen.java

@@ -1538,6 +1538,10 @@ public class ChangeScreen extends Screen {
       nm = JsArray.createArray().cast();
     }
 
+    if (om.length() == nm.length()) {
+      return;
+    }
+
     if (updateAvailable == null) {
       updateAvailable =
           new UpdateAvailableBar() {