title: NSTextAlignmentJustified to UILable textAligment on iOS6 will crash
body: <p>I am use Xcode4.5 and iOS6 now, the iOS6 have change the UILable's textAlignment, </p>
  
  <pre><code>label.textAlignment = NSTextAlignmentJustified;
  </code></pre>
  
  <p>The code will crash on iPhone 6.0 Simulator with ios6 SDK. but not crash on iPhone 5.0 Simulator with iOS6 SDK.</p>
  
  <p>The iOS6 support NSTextAlignmentJustified,  but why will crash?</p>