Try to use SSL if the server supports it.

util.c

@@ -329,6 +329,7 @@ json_t *json_rpc_call(CURL *curl, const char *url,
 	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
 	curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, resp_hdr_cb);
 	curl_easy_setopt(curl, CURLOPT_HEADERDATA, &hi);
+	curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_TRY);
 	if (userpass) {
 		curl_easy_setopt(curl, CURLOPT_USERPWD, userpass);
 		curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);