make sure a tag cannot be a parent of itself, bug #3412
make sure a tag cannot be a parent of itself, bug #3412

openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server