title: unrecognized selector sent to instance at facebook login manager in facebook sdk 4.6 on iOS9
body: <p>Hi I have just upgraded my app to iOS 9 and using Facebook's latest SDK (version 4.6) for facebook login. </p>
  
  <p>I am using custom login button hence using the LoginManager class for the same. With the previous version it was working fine but now my app gets crashed whenever I press the login button saying "unrecognized selector sent to instance"</p>
  
  <p>Below is the code I am using in my GameScene class to login.</p>
  
  <pre><code>var fbLogin = FBSDKLoginManager()
  func onClickFBLogin(){
          let vc = self.view?.window?.rootViewController
          fbLogin.logInWithReadPermissions(["public_profile"] as [AnyObject], fromViewController: vc, handler: {(result:FBSDKLoginManagerLoginResult!, error:NSError!) -&gt; Void in
              if(error != nil){
                  print("Facebook login error \(error)")
              } else if(result.isCancelled){
                  print("Facebook login cancelled")
              } else{
                  print("facebook login successful")
                  if(self.isSaveMeButtonPressed){
                      print("facebook login successful")
                  }
              }
          })
  }
  </code></pre>
  
  <p>The app is crashing with below log on Xcode.</p>
  
  <blockquote>
    <p>[FBSDKLoginManager logInWithReadPermissions:fromViewController:handler:]: unrecognized selector sent to instance 0x7f82e51251e0</p>
  </blockquote>
  
  <p>Anyone facing the same issue? Or someone who can help me sort this issue?</p>
  
  <p>Thanks in advance. </p>