title: Facebook ShareDialog always returns .canceled on completion
body: <p>Share dialog opens facebook app and despite content is shared successfuly I always receive <em>.cancelled</em> callback. In both cases - when I cancel sharing and when sharing is successfull. Any idea what is wrong?
  Pods versions:</p>
  
  <pre><code>Using Bolts (1.8.4)
  Using FBSDKCoreKit (4.20.2)
  Using FBSDKLoginKit (4.20.2)
  Using FBSDKShareKit (4.20.2)
  Using FacebookCore (0.2.0)
  Using FacebookLogin (0.2.0)
  Using FacebookShare (0.2.0)
  </code></pre>
  
  <p>Snippet for showing dialog:</p>
  
  <pre><code>    @IBAction func onShareClicked(_ sender: UIButton) {
      do{
          var myContent = LinkShareContent(url: URL(string: "https://www.facebook.com/8MinuteWorkoutChallenge")!)
          myContent.hashtag = Hashtag("#8MWC")
  
          let shareDialog = ShareDialog(content: myContent)
          shareDialog.mode = .native
          shareDialog.failsOnInvalidData = true
          shareDialog.completion = { result in
              switch result {
              case .success:
                  print("Share succeeded")
              case .failed:
                  self.shareButton.isHidden = true
              case .cancelled:
                  print("Share cancelled")
              }
          }
  
          try shareDialog.show()
      } catch {
          print("Error: \(error)")
      }
  }
  </code></pre>
  
  <p>config</p>
  
  <pre><code>&lt;key&gt;LSApplicationQueriesSchemes&lt;/key&gt;
  &lt;array&gt;
      &lt;string&gt;fbapi&lt;/string&gt;
      &lt;string&gt;fb-messenger-api&lt;/string&gt;
      &lt;string&gt;fbauth2&lt;/string&gt;
      &lt;string&gt;fbshareextension&lt;/string&gt;
  &lt;/array&gt;
  &lt;key&gt;CFBundleURLTypes&lt;/key&gt;
  &lt;array&gt;
      &lt;dict&gt;
          &lt;key&gt;CFBundleURLSchemes&lt;/key&gt;
          &lt;array&gt;
              &lt;string&gt;fb188***33776&lt;/string&gt;
          &lt;/array&gt;
      &lt;/dict&gt;
  &lt;/array&gt;
  &lt;key&gt;FacebookAppID&lt;/key&gt;
  &lt;string&gt;18851***3776&lt;/string&gt;
  &lt;key&gt;FacebookDisplayName&lt;/key&gt;
  &lt;string&gt;8MWC&lt;/string&gt;
  </code></pre>