title: Cannot set default background image for MFMailComposeViewController
body: <p>I'm using a <code>MFMailComposeViewController</code> to compose a mail and add an attachment in my app.</p>
  
  <p>I've got this code in my <code>AppDelegate.m</code></p>
  
  <pre><code>[[UINavigationBar appearance] setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
  [[UINavigationBar appearance] setShadowImage:[UIImage new]];
  [[UINavigationBar appearance] setTranslucent:NO];
  [[UINavigationBar appearance] setBarTintColor:[UIColor colorWithRed:0x0A/255.0f green:0x13/255.0f blue:0x1A/255.0f alpha:1]];
  </code></pre>
  
  <p>Then I'm using this code to create the  <code>MFMailComposeViewController</code> in another <code>UIViewController</code></p>
  
  <pre><code>MFMailComposeViewController *mailViewController = [[MFMailComposeViewController alloc] init];
  
  [mailViewController.navigationController.navigationBar setBackgroundImage:nil forBarMetrics:UIBarMetricsDefault];
  
  mailViewController.mailComposeDelegate = self;
  [self presentViewController:mailViewController animated:YES completion:nil];
  </code></pre>
  
  <p>However, the <code>UINavigationBar</code> in the <code>MFMailComposeViewController</code> is dark, how come it doesn't "reset" itself to the background I specify before presenting it? Is it inheriting the color of the current <code>UIViewController</code>?</p>