Switch back to hawkey for version comparison, prep for 1.2.0
    
    hawkey's version comparison is fixed now, and this at least
    means we only have *one* awkward not-in-pypi library to deal
    with (and we don't have to deal with the rpm library changing
    its goddamn setuptools name).
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>