http_request: add timeout option
    
    httplib.HTTPConnection supports timeout option so _httplib_request can
    be updated to allow passing connection keyword arguments to
    connection_factory.
    
    We need connection timeout for cases when reply from server is not
    received on time to ask again and not to wait for infinity.
    
    https://pagure.io/freeipa/issue/6766
    
    Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>