fix(tests): fixed a broken test

Author: vsavkin

modules/angular2/test/di/async_spec.js

@@ -161,7 +161,7 @@ export function main() {
  UserController
  ]);
 
- injector.asyncGet(UserList).then(() => {
+ injector.asyncGet(UserList).then((_) => {
  expect(() => { injector.get(UserController); }).not.toThrow();
  async.done();
  });