py3: update_mod_nss_cipher_suite: ordering doesn't work with None
    
    Py3 doesn't support ordering with None value
    
    https://fedorahosted.org/freeipa/ticket/4985
    
    Reviewed-By: Jan Cholasta <jcholast@redhat.com>
    Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>