Remove all duplication and normalize id/path to prevent further problems.
  Set int_index to 1 on all region categories to facilitate the migration script, to know
      which ones are the "latest". This flagging allow us search for a proper category
  when cleaning up.

  portal_categories/region/** was added to keep path to prevent categories be removed
  during the upgrade. This should be done (or not) by a migration script later on, since
  it is required to update the related objects.