Add missing teardown method to gr-change-actions_test

Change-Id: I4040ae7c1e856e91dbd8aa1c6d6d8c89957125fe

polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html

diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html
index cc94404..5aba1a0 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html
@@ -98,6 +98,10 @@
       server.respond();
     });
 
+    teardown(function() {
+      server.restore();
+    });
+
     test('submit, rebase, and cherry-pick buttons show', function(done) {
       flush(function() {
         var buttonEls = Polymer.dom(element.root).querySelectorAll('gr-button');