Move 'rpm-python' from install to test requires (#1528508)
    
    RPM upstream, spectacularly idiotically, changed the 'name' of
    this module (in setuptools/pkg_resources terms), making it flat
    out impossible to express a dependency on it that will work
    properly. To try and keep things working as best we can, move
    the requirement from install.requires to test.requires; this
    will at least mean the tests work so long as the module can be
    found under the 'rpm-python' name, while meaning the consumer
    will work even when it's not around. I hope.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>