title: crash on "UICollectionView dequeueReusableCellWithReuseIdentifier:forIndexPath"
body: <p>I have a UICollectionView, while the cell is reused, then crashed.
  Below is the stack while crash.</p>
  <p>0
  libobjc.A.dylib
  objc_msgSend + 32</p>
  <p>1
  UIKitCore
  -[UIView(Animation) _removeAllAnimations:] + 100</p>
  <p>2
  UIKitCore
  -[UIView(Animation) _removeAllAnimations:] + 244</p>
  <p>3
  UIKitCore
  -[UIView(Animation) _removeAllAnimations:] + 244</p>
  <p>4
  UIKitCore
  -[UIView(Animation) _removeAllAnimations:] + 244</p>
  <p>5
  UIKitCore
  -[UIView(Animation) _removeAllAnimations:] + 244</p>
  <p>6
  UIKitCore
  -[UIView(Animation) _removeAllAnimations:] + 244</p>
  <p>7
  UIKitCore
  -[UIView(Animation) _removeAllAnimations:] + 244</p>
  <p>8
  UIKitCore
  -[UICollectionViewCell prepareForReuse] + 228</p>
  <p>9
  UIKitCore
  -[UICollectionView _dequeueReusableViewOfKind:withIdentifier:forIndexPath:viewCategory:] + 400</p>
  <p>10
  UIKitCore
  -[UICollectionView dequeueReusableCellWithReuseIdentifier:forIndexPath:] + 104</p>
  <p>11
  myapp
  -[myCollectionView collectionView:cellForItemAtIndexPath:]</p>
  <p>Can you help me? I'm really not understand why crash in here.</p>