error fix

mock/_createProductionServer.js

@@ -14,5 +14,10 @@ Object.keys(modules).forEach((key) => {
  * Used in a production environment. Need to manually import all modules
  */
 export function setupProdMockServer() {
+  // https://kgithub.com/nuysoft/Mock/issues/301
+  // 避免 _xhr.upload.addEventListener is not a function
+  var xhr = new window._XMLHttpRequest();
+  window.XMLHttpRequest.prototype.upload = xhr.upload;
+
   createProdMockServer(mockModules);
 }