title: Firebase - Deleting and reinstalling app does not un-authenticate a user
body: <p>After authenticating a user with the following code (below is a trimmed version of my code, so only the successful login logic is shown)...</p>
  
  <pre><code>let firebaseReference = Firebase(url: "https://MY-FIREBASE.firebaseio.com")
  </code></pre>
  
  <p>&nbsp;</p>
  
  <pre><code>FBSession.openActiveSessionWithReadPermissions(["public_profile", "user_friends"], allowLoginUI: true,
      completionHandler: { session, state, error in
  
          if state == FBSessionState.Open {
              let accessToken = session.accessTokenData.accessToken
              firebaseReference.authWithOAuthProvider("facebook", token: accessToken,
                  withCompletionBlock: { error, authData in
  
                      if error != nil {
                          // Login failed.
                      } else {
                          // Logged in!
                          println("Logged in! \(authData)")
                      }
              })
          }
      })
  }
  </code></pre>
  
  <p>(I.e. Launching and running the app, logging in successfully).</p>
  
  <p>If you then delete the app and reinstall it on the same device, this call - which I am using in the app delegate to determine if a user is logged in - will always return that they are logged in.</p>
  
  <pre><code>if firebaseReference.authData == nil {
      // Not logged in
  } else {
      // Logged in
  }
  </code></pre>
  
  <p>Why is that? I would have thought deleting the app and reinstalling it should wipe all data.</p>
  
  <p>If you reset the Content and Settings in the iOS simulator, and the install the app, the <code>firebaseReference.authData</code> property will once again be <code>nil</code>.</p>