title: App crash when change permission AddressBook in Settings
body: <p>Swift (iOS 8 / iOS 9): App crash when I change permission AddressBook in Settings on real device</p>
  
  <p><img src="https://i.stack.imgur.com/C4xRl.png" alt="Error when permission change in Settings">
  <img src="https://i.stack.imgur.com/xggpt.png" alt="Code">
  <img src="https://i.stack.imgur.com/DBfyz.png" alt="Code"></p>