Since introducing distro. installs, we have two different role
inclusions, one for distro and one for source. It seems that this
was done to send a different set of variables to each run.
With the recent build changes, all the branch variables are already
included using from openstack_services.yml so there's no need to
redefine them.
This means we can bring the two includes back to a normal role
reference, which resolves a few issues around using import_role and
brings back the ability to use tags only with this playbook.
Change-Id: I6c6651ce923530b1d2395cd387faf6e74c9b17d8
1f1cca42c5