Comment 2 for bug 1646161

The problem is that the test wants to checkout the juju branch and change it. This is WRONG. We don't release branches, we release tarfiles that are not like the branches. A recent change to juju-uitest is forcing an update when it is both wrong and impossible.

uitest/suite/juju.py:56: in setUpClass
    'bootstrap', cloud_name, cls.controller_name)
uitest/suite/commands.py:85: in juju
    branch=os.getenv('JUJU_BRANCH', None))
uitest/gocommand.py:71: in build
    _update_project(src_path, repo, branch)
uitest/gocommand.py:129: in _update_project
    git.checkout(src_path, branch)

I see os.getenv('JUJU_BRANCH', None). I want to set this to 'tarfile' and have _update_project() exit early before it calls git.