Steps to reproduce:

1. Install fresh eZ Platform v2.5.
2. Create any Content -> remember content_id.
3. Query the ezcobj_state_link table.
4. Search for the link for the remembered content ID.
5. Link exists.
6. Delete this content and empty the trash.

Result:
ezcobj_state_link record is still there.

Expected result:
ezcobj_state_link should be deleted.