Fix lint warning

Change-Id: I1747844a0f92d8a6c36ea2b2b70d789b60e992e3
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 2720b29..9643e93 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
@@ -329,7 +329,7 @@
         element._handleCherrypickConfirm();
 
         assert.equal(element.$.confirmCherrypick.$.messageInput.value,
-            "foo message");
+            'foo message');
 
         assert.deepEqual(fireActionStub.lastCall.args, [
           '/cherrypick', action, true, {