title: Setting the keyWindow rootViewController not working in iOS8
body: <p>In my app I need the user to login and logout. When I want the user to logout, I delete their credentials and then:</p>
  
  <pre><code>ZSSLogin *login = [self.storyboard instantiateViewControllerWithIdentifier:@"ZSSLogin"];
  [[UIApplication sharedApplication].keyWindow setRootViewController:[[UINavigationController alloc] initWithRootViewController:login]];
  </code></pre>
  
  <p>Which is suppose to replace the current <code>rootViewController</code> (tabBarController) with the login <code>viewController</code>. </p>
  
  <p>On iOS7 this works correctly. But, in iOS8 it will show the login VC for a split second, but then return back to the tabBarController like nothing happened.</p>
  
  <p>Any ideas on what is going on?</p>