title: UIDocumentsInteractionController shows iBooks but doesn't open it
body: <p>My UIDocumentsInteractionController is working as far as  presenting an action sheet with a button that says "iBooks" but when I click on that button, it just dismisses and it doesn't take me to iBooks. Here's my code:</p>
  
  <pre><code>NSString *filenamePath =[NSString stringWithFormat:@"temp.%@", [[file path] pathExtension]];
  
      NSString *docDir = [DataCenter getDocumentsDirectoryPath];
  
      NSString *fullPath = [docDir stringByAppendingPathComponent:filenamePath];
  
      NSURL *url = [NSURL fileURLWithPath:fullPath];
      UIDocumentInteractionController *c = [UIDocumentInteractionController interactionControllerWithURL:url];
  
      BOOL success = [c presentOpenInMenuFromBarButtonItem:buttonBack animated:YES];
  </code></pre>
  
  <p>What am I doing wrong? 
  Thanks</p>