title: dismissViewControllerAnimated not work using quickdialog
body: <p>I am using QuickDialog to push a login form. Everything is working except the view controller can not be dismissed. The code like this:</p>
  
  <pre><code>- (void)onLogin:(QButtonElement *)buttonElement
  {
      [self loading:YES];
      Info *info = [[Info alloc] init];
      [self.root fetchValueUsingBindingsIntoObject:info];
      [self.client loginWithUsername:info.login password:info.password onSuccess:^(NSDictionary *result) {
          NSLog(@"user signed in");
          [self loading:NO];
          [self dismissViewControllerAnimated:YES completion:nil];
      } onFailure:^(NSError *error) {
          NSLog(@"login error");
      }];
  }
  </code></pre>
  
  <p>And I am using these codes to push this view controller</p>
  
  <pre><code>QRootElement *root = [[QRootElement alloc] initWithJSONFile:@"loginform"];
  LoginController *loginController = (LoginController *)[QuickDialogController controllerForRoot:root];
  [self.navigationController pushViewController:loginController animated:YES];
  </code></pre>