title: presentViewController: crash on iOS <6 (AutoLayout)
body: <p>This is a weird crash I am getting. The crash happens when I press a button that goes to a certain ViewController. The line which it crashes on is:</p>
  
  <pre><code>DestinationInformationViewController *info = [[DestinationInformationViewController alloc] init];
  [info setModalTransitionStyle: UIModalTransitionStyleCrossDissolve];
  [self presentViewController:info animated:YES completion: nil]; // CRASHES HERE
  [info release];
  </code></pre>
  
  <p>The crash trace is:</p>
  
  <p><code>*** Terminating app due to uncaught exception 'NSInvalidUnarchiveOperationException', reason: 'Could not instantiate class named NSLayoutConstraint'
  *** First throw call stack:
  (0x3758288f 0x35287259 0x37582789 0x375827ab 0x3153d54d 0x3153d6bb 0x3153d423 0x314ce001 0x3143c3c7 0x31319c59 0x3128fc17 0x3129a267 0x3129a1d5 0x3133959b 0x31338367 0x84091 0x374dc3fd 0x31271e07 0x31271dc3 0x31271da1 0x31271b11 0x31272449 0x3127092b 0x31270319 0x31256695 0x31255f3b 0x33c9822b 0x37556523 0x375564c5 0x37555313 0x374d84a5 0x374d836d 0x33c97439 0x31284cd5 0x82bb3 0x71200)
  terminate called throwing an exception(gdb) Could not instantiate class named NSLayoutConstraint</code></p>
  
  <p>NOTE: This crashes on my iPhone 4 iOS 5.1 but not on my iPhone 4S iOS 6 Beta 2</p>