Adding request to error objects when it is available

lib/core/enhanceError.js

@@ -6,14 +6,16 @@
  * @param {Error} error The error to update.
  * @param {Object} config The config.
  * @param {string} [code] The error code (for example, 'ECONNABORTED').
+ @ @param {Object} [request] The request.
  @ @param {Object} [response] The response.
  * @returns {Error} The error.
  */
-module.exports = function enhanceError(error, config, code, response) {
+module.exports = function enhanceError(error, config, code, request, response) {
   error.config = config;
   if (code) {
     error.code = code;
   }
+  error.request = request;
   error.response = response;
   return error;
 };