Use an env lookup to determine the OSA version
Use an env lookup to determine the OSA version

This is about as fast as the current static code, and doesn't
require bumping at every release.

Change-Id: I75657c6dae2c6246ec2513f4ec452a4c354d638b

openstack/openstack-ansible,openstack/openstack-ansible,stackforge/os-ansible-deployment,stackforge/os-ansible-deployment