Allow xfer of parms from httpclient request header to response header

As of [HTTPClient ed9c65c](https://github.com/nahi/httpclient/commit/ed9c65c440c7c03905e9df117d642c536ca92de9#diff-b39809a3be5ff11e15c4c772d6c6b2a8), HTTP::Message::Headers::init_response makes provision to transfer request_method, request_uri, and request_query from a request header to the response header, but the adapter isn't passing the request during build_httpclient_response; and so (e.g.) response.header.request_uri is always nil.