More tweaking for this damn no root password spoke situation
    
    Previous approach wouldn't work for tests that run after the
    install test...let's just set a password from a chroot after
    install completes. Don't really like this as it changes the
    'real' install process a bit, but it's the least invasive short
    term fix at least. We can maybe do something more sudo-y later
    with a bit more thought.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>