title: View lose cornerRadius with Animation of UIViewAnimationOptionTransitionFlipFromLeft on iOS 8
body: <p>In the code, I have set: </p>
  
  <pre><code>imageView.layer.masksToBounds = YES;
  imageView.layer.cornerRadius = imageView.frame.size.width/2;
  </code></pre>
  
  <p>And run it in animation block:</p>
  
  <pre><code>[UIView transitionWithView:imageView
                        duration:1.0
                         options:UIViewAnimationOptionTransitionFlipFromLeft
                      animations:nil
                      completion:^(BOOL finished) {
                          imageView.hidden = YES;
                      }];
  </code></pre>
  
  <p>But when running on iOS 8, the <code>imageView</code> is back to normal, means there is no <code>cornerRadius</code> for <code>imageView</code>.</p>
  
  <p>Could anyone tell me why?</p>