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: Ie4f408ab3feab6918f6d7f3ec5376e1b0d18448a

openstack/dragonflow,openstack/dragonflow,openstack/dragonflow