It can be accomplished by changing a bit the translation_tabs_form_alter() function like this:

function translation_tabs_form_alter(&$form, $form_state, $form_id) 
{

  if(!translation_supported_type($form['#node']->type)) return; /** LINE ADDED BY IDYNAMIC */

  if ($form['#id'] == 'node-form') {
    translation_tabs_create_tabs($form);
  }

}