remove the master from managed topology during uninstallation
    
    In managed topology, calling `ipa-server-install --uninstall` will cause the
    master to remove itself from the topology by calling `server_del` behind the
    scenes.
    
    https://fedorahosted.org/freeipa/ticket/5588
    
    Reviewed-By: Martin Basti <mbasti@redhat.com>