Zuul: add file extension to playbook path
Zuul: add file extension to playbook path

Zuul now supports including the file extension on the playbook path
and omitting the extension is now deprecrated.  Update references
to include the extension.

Change-Id: I9760e93bfcd8a175bb97a8ee55ce9ff19d8d3923

openstack/ironic,openstack/ironic