RFC: Fix leaks of mako_notification in handle_notify()

[psqli]

Unify clean up on error with goto statements.

Is freeing the expected behavior?

[psqli]

Also, the commit 4dc382ecc7585d729723 ("Allow create_notification outside handle_notify") introduced strdup() calls inside reset_notification(), which is called by destroy_notification() just before notif is freed.