title: Login with Facebook cannot do login 2nd time after logout
body: <p>My case is, </p>
  
  <ul>
  <li>launch an app</li>
  <li>tap on login with facebook button</li>
  <li>The login with Facebook is done successfully.</li>
  </ul>
  
  <p>Now,</p>
  
  <ul>
  <li>Do logout by click on the logout icon. (It redirect to login screen back)</li>
  </ul>
  
  <p>After log out, </p>
  
  <ul>
  <li>Do tap on the Facebook button to re-login and nothing is happening.</li>
  </ul>
  
  <p>While looking on Logcat, 
  it shows</p>
  
  <blockquote>
    <p>E/LoginFragment: Cannot call LoginFragment with a null calling package. This can occur if the launchMode of the caller is singleInstance.</p>
  </blockquote>