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>