title: text color of disabled uibarbuttonitem is always the color of the normal state
body: <p>i wrote in my code</p>
  
  <pre><code>[[UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], nil]  setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor lightGrayColor], NSFontAttributeName:[UIFont boldSystemFontOfSize:16.0f]} forState:UIControlStateDisabled];
  
  [[UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], nil]  setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor blueColor], NSFontAttributeName:[UIFont boldSystemFontOfSize:16.0f]} forState:UIControlStateNormal];
  </code></pre>
  
  <p>but the text color is always blue despite the baritem being disabled.</p>
  
  <p>I'm programming in xcode 5 and ios7 </p>