Don't report on non-live changes dequeueing

If a non-live change was removed from the queue because one of
its dependencies was removed, do not report on that change.  The
live change will eventually be removed for the same reason and
it will report.  Once is all that is needed.

This should not normally happen, but we have seen it occur when
dependencies have somehow changed behind zuul's back, possible
because of an error in Gerrit.

Change-Id: Ibb8daafb064e841606083d648b81389966d5333e
diff --git a/zuul/scheduler.py b/zuul/scheduler.py
index 25f8192..131ad62 100644
--- a/zuul/scheduler.py
+++ b/zuul/scheduler.py
@@ -1365,10 +1365,11 @@
             self.cancelJobs(item)
             self.dequeueItem(item)
             self.pipeline.setDequeuedNeedingChange(item)
-            try:
-                self.reportItem(item)
-            except MergeFailure:
-                pass
+            if item.live:
+                try:
+                    self.reportItem(item)
+                except MergeFailure:
+                    pass
             return (True, nnfi, ready_ahead)
         dep_items = self.getFailingDependentItems(item)
         actionable = change_queue.isActionable(item)