Merge branch 'stable-2.12'

* stable-2.12:
  Fix missing query results when label=0 and related relational operators
  OutputStreamQuery: Only return current patch set when visible to user
  Fix NPE in SubmitRuleEvaluator
  Protect the TrackingFooters.extract from null input parameter
  Fix index-activate and index-start documentation
  Reapply: Revert "Use changeRefsById to track existing revisions"

Change-Id: I9f8e82f38c2ec4cf273a6a29c7dc634d8c28b6c1

gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/AbstractDaemonTest.java

@@ -496,6 +496,11 @@ public abstract class AbstractDaemonTest {
     revision(r).submit();
   }
 
+  protected PushOneCommit.Result amendChangeAsDraft(String changeId)
+      throws Exception {
+    return amendChange(changeId, "refs/drafts/master");
+  }
+
   protected ChangeInfo info(String id)
       throws RestApiException {
     return gApi.changes().id(id).info();