Currently builtins_db is created in the catalogd initialization. But later on when catalogd calls reset(), catalogd will replace its dbCache with DBs from HMS. As a result, a delete builtins_db operation is always in the initial catalog update sent to statestore. Though statestore doesn't send it to impalad because the initial catalog is not a delta and doesn't include delete operations, it's a potential problem. We should remove builtins db from catalogd because it's not needed there.