Shallow cloning doesn't work during repo-build

[Jean-Philippe Evrard]

The shallow cloning (depth argument of 1) in the repo-build doesn't work with SHAs, because shas aren't always HEADs of branches or other special references.

If we were to move to use tags instead of SHAs for the playbooks/defaults/repo_packages/*.yml files, the shallow cloning would work, and time would be gained.

A time gain would be appreciable for stable branches, and still respects the spirit of the openstack-ansible build from sources. Any deployer could override with its own sha if need be.

[Andrew Bonney (andrewbonney)]

Shallow clones have been changed to use 'shallow_since' dates more recently. This is likely no longer an issue.