Reset play attribute on callback plugins when a play fails.

lib/ansible/playbook/__init__.py

@@ -322,6 +322,7 @@ class PlayBook(object):
             ansible.callbacks.set_play(self.runner_callbacks, play)
             if not self._run_play(play):
                 break
+
         ansible.callbacks.set_play(self.callbacks, None)
         ansible.callbacks.set_play(self.runner_callbacks, None)