Merge branch 'tc/missing-http-proxyauth'

We did not check the curl library version before using
CURLOPT_PROXYAUTH feature that may not exist.

* tc/missing-http-proxyauth:
  http: support curl < 7.10.7

http.c

@@ -405,7 +405,9 @@ static CURL *get_curl_handle(void)
 
 	if (curl_http_proxy) {
 		curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
+#if LIBCURL_VERSION_NUM >= 0x070a07
 		curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
+#endif
 	}
 
 	set_curl_keepalive(result);