title: Sharing via UIActivityViewController to Twitter/Facebook etc. causing crash
body: <p>On iOS8 I'm using a UIActivityViewController to share a UIImage to Facebook/Twitter etc. It seemed to be working fine, but today it suddenly started crashing when running the code on my iPad.  However, it still works as expected in the simulator.</p>
  
  <p>My code:</p>
  
  <pre><code>UIActivityViewController *controller =
  [[UIActivityViewController alloc]
   initWithActivityItems:@[text, url, myImage]
   applicationActivities:nil];
  
  [self presentViewController:controller animated:YES completion:nil];
  </code></pre>
  
  <p>Upon crashing, Xcode spits out:</p>
  
  <blockquote>
    <p>Discovered extensions: {(
         {id = com.apple.share.Facebook.post},
         {id = com.apple.share.Twitter.post},
         {id = com.apple.share.TencentWeibo.post},
         {id = com.apple.share.SinaWeibo.post} )} for attributes: {
        NSExtensionActivationRule =     {
            extensionItems =         (
                            {
                    attachments =                 (
                                            {
                            registeredTypeIdentifiers =                         (
                                "public.image"
                            );
                        },
                                            {
                            registeredTypeIdentifiers =                         (
                                "public.plain-text"
                            );
                        },
                                            {
                            registeredTypeIdentifiers =                         (
                                "public.url"
                            );
                        }
                    );
                }
            );
        };
        NSExtensionPointName =     (
            "com.apple.share-services",
            "com.apple.ui-services",
            "com.apple.services"
        ); } 2014-08-07 21:38:59.208 collageTest[279:11021] LaunchServices: invalidationHandler called 2014-08-07 21:38:59.212
    collageTest[279:11016] Discovered extensions: {(
         {id = com.apple.share.Flickr.post},
         {id = com.apple.mobileslideshow.StreamShareService},
         {id = com.apple.share.Twitter.post},
         {id = com.apple.share.Facebook.post},
         {id = com.apple.share.Vimeo.post},
         {id = com.apple.share.SinaWeibo.post},
         {id = com.apple.share.TencentWeibo.post} )} for attributes: {
        NSExtensionPointName = "com.apple.share-services"; } 2014-08-07 21:38:59.216 collageTest[279:11021] LaunchServices:
    invalidationHandler called</p>
  </blockquote>