Tweak remote question fetching

tasks.py

@@ -64,6 +64,8 @@ class Tasks:
         dt = parser.parse(question.closed or question.endTime).astimezone(timezone.utc)
         minutes = int((dt - now).total_seconds() / 60)
 
+        if minutes > 0:
+            # Only push the task if the poll is not ended yet
             p.push(
                 question.id, "/task/fetch_remote_question", delay=minutes
             )  # XXX: delay expects minutes