Display latest result of branch list screen's filter

Before the fix the branch list screen displays branches based on the
filter but sometimes failed to display the latest result when filter is
typed fast and server is slow enough.

This change ensures that the branch list screen always displays the
latest result of the filter.

Change-Id: Iea902adea7f5e9753a54e140ebc0cbfff1f12239

gerrit-gwtui/src/main/java/com/google/gerrit/client/admin/ProjectBranchesScreen.java

@@ -258,8 +258,10 @@ public class ProjectBranchesScreen extends ProjectScreen {
         Query q = new Query(filterTxt.getValue());
         if (match.equals(q.qMatch)) {
           q.start(start);
-        } else if (query == null) {
-          q.run();
+        } else {
+          if (query == null) {
+            q.run();
+          }
           query = q;
         }
       }