Fix issue 1446: honor ports given in SRV responses.
* common/http.c (send_request, connect_server, http_open): Use a struct srv instead of a single srvtag so we can pass the chosen host and port back to the caller. (connect_server): Use the proper port in the HAVE_GETADDRINFO case. * keyserver/curl-shim.c (curl_easy_perform): Use struct srv and log chosen host and port. * keyserver/gpgkeys_hkp.c (main): Properly take the port given by SRV.