debian: add support
debian: add support

This patch adds support for this role to be able to deploy on
Debian Stretch.

Change-Id: I4ee130917373c643ae80bab7a778cc6f35868dc8
Needed-By: I135ea73604890eae5e9e2a7cdcab81b2b39ad426

openstack/openstack-ansible-lxc_container_create,openstack/openstack-ansible-lxc_container_create