Cleanup stray PHP 4-style references in hook calls for navigation bars. We can't...

Cleanup stray PHP 4-style references in hook calls for navigation bars. We can't replace the live action from here, and don't need a reference to keep the object mutable. Dumping the references helps ensure we don't end up getting errors when things calling the hooks might forget to use the reference and the PHP error reporting settings expose this fact at us.