Have to disagree with the previous answer: It actually does make sense, but not completely.
AES encryption here would add an additional layer to password security, that is based on information not stored in the database (I assume you would not put the AES key to the same database with passwords). There are several scenarios where password database might be compromised without gaining access to the application configuration. (SQL injections, database on a different server, access to database backups, etc.)
Even when using bcrypt's user-specific salt, weak passwords are still relatively easy to crack. And there will be lots of weak passwords in any password database.
The point that does not make sense: Why symmetric encryption, when you simply could append the secret key to the password before running BCrypt? So, the same security level is gained by:
$hash = $bcrypt->hash('some-password-here' . 'crypto_key');
Read more: http://blog.mozilla.org/webappsec/2011/05/10/sha-512-w-per-user-salts-is-not-enough/