Redirect after comment submit according to value of query string in comment form URL?
After More deep debugging I found that action of comment from is set to 


  comment/reply/nodeid


So with below URL's:


  http://www.example.com/comment/reply/208943?destination=newsroom#comment-form
  
  http://www.example.com/comment/reply/208943?destination=sections#comment-form


My query string variable destination  is lost or either at form submit it shows null because from moves to action URL where no query string was set.

To solve this I have added query string in action URL which works very well :

function my_module_form_alter(&amp;$form, $form_state, $form_id) {
   if ($form_id == "comment_node_link_form") {
      $form['#action'] = $form['#action'] . '?destination=' . $_GET['destination'];
  }
}


ie: All I have to do is add required query string to $form['#action']

Hope this will help any one who is trying similar solution.