Make sure Ansible tests only use cirros images
Make sure Ansible tests only use cirros images

It's possible enabling OpenStack things can cause other images other
than cirros to be made available (looking at you Magnum). We should
make sure our Ansible tests only look for Cirros.

Change-Id: Iefc01f8033629937552861366b9ddaac8058b249

openstack/python-openstacksdk,stackforge/python-openstacksdk,openstack-infra/shade,openstack-infra/shade,stackforge/python-openstacksdk,dtroyer/python-openstacksdk,dtroyer/python-openstacksdk,openstack/python-openstacksdk