Use release number in name of Rawhide images, not 'rawhide'
    
    After looking at the openQA side, I think I prefer this way of
    doing things overall. If we use 'rawhide' in the filenames, we
    have to use 'Rawhide' as the VERSION on openQA side, and that
    involves quite a lot of surgery. If we can use the release number
    as the VERSION on openQA side for Rawhide updates, that seems to
    work better, and tie in better with Bodhi.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>