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.
Migration script (Upgrade Constraint) will move the categories from the old values to proper ones, and expire the old ones (when applicable).