When doing the role upgrade, we run every playbook with current's
branch ansible. This is normal for the infrastructure bits (which
are running on current branch), but not for the installation of
the previous branch's role, which should use previous branch's
environment.
Change-Id: I88e2616db193487905e1e1552695ec4847bcb4f9
Depends-On: I7ebb045885dd645b820de2b7f75b46c755c015f6
Related-Bug: #1741471