Cinder ansible waits for bootstrap container on all hosts

Bootstrap task runs bootstrap container on one host but
waits for its exit on all machines in inventory. This
gives error about non-existing container id.

Change-Id: Ie06c4da470c2e109d13b029fa674373b255653f3
Closes-Bug: #1487387

ansible/roles/cinder/tasks/bootstrap.yml

@@ -71,6 +71,7 @@
 - name: Waiting for bootstrap container to exit
   command: docker wait bootstrap_cinder
   when: database.stdout.find('localhost | SUCCESS => ') != -1 and (database.stdout.split('localhost | SUCCESS => ')[1]|from_json).changed
+  run_once: True
 
 - name: Cleaning up Cinder boostrap container
   docker: