1eb4c6a [frontend] when deleting an outdated chroot, NULL the remove_after field

Authored and Committed by frostyx 5 months ago
    [frontend] when deleting an outdated chroot, NULL the remove_after field
    
    We will lose the timestamp of when the chroot should have been deleted
    (which doesn't equal the timestamp when the chroot actually was
    deleted, but can have some aproximate value for statistics), in order to
    not create delete_chroot action for already deleted chroots.