protocols we handle. Directly pass them to curl or fake-curl and see if
an error comes back.
* curl-shim.h, curl-shim.c (handle_error), ksutil.c (curl_err_to_gpg_err):
Add support for CURLE_UNSUPPORTED_PROTOCOL in fake curl.
* Makefile.am: Don't need -DFAKE_CURL any longer since it's in config.h.