Don't run post_playbook if ansible-playbook is aborted

If ansible-playbook returns -9, the job has been aborted. No need to
continue and upload logs.

Change-Id: I9326f77ae51bb80cce30a825dc8360bf7be533c4
Signed-off-by: Paul Belanger <pabelanger@redhat.com>
diff --git a/zuul/launcher/ansiblelaunchserver.py b/zuul/launcher/ansiblelaunchserver.py
index b53f314..83236f8 100644
--- a/zuul/launcher/ansiblelaunchserver.py
+++ b/zuul/launcher/ansiblelaunchserver.py
@@ -1128,6 +1128,9 @@
             # AnsibleHostUnreachable: We had a network issue connecting to
             # our zuul-worker.
             return None
+        elif ret == -9:
+            # Received abort request.
+            return None
         return ret == 0
 
     def runAnsiblePostPlaybook(self, jobdir, success):