title: FBSession requestNewPublishPermissions how to handle "Skip" user action
body: <p>I found interesting issue.</p>
  
  <p>When i'm requesting new publish permissions, fb sdk shows dialog with the "Skip" button.
  I'm handling it like this</p>
  
  <pre>
  <code>
          [[[appDelegate facebook] session] requestNewPublishPermissions:permissions
                                                         defaultAudience:FBSessionDefaultAudienceEveryone
                                                       completionHandler:^(FBSession *session, NSError *error)
           {
               if (!error)
               {
                    //do smth if there is no error
               }
           }];
  
  </code></pre>
  
  <p>But when user pressed "Skip" inside the dialog - error is nil.</p>
  
  <p>How to handle it? Maybe i don't understand smth.
  Thx.</p>