Bug 36995: Correct parameter name for library EAN deletion

Bug 36995: Correct parameter name for library EAN deletion

This patches removes the "cud-" prefix from the "delete_confirm"
parameter check in Library EAN management. The confirm step is a GET
operation.

To test, apply the patch and restart services;

- Go to Administration -> Library EANs.
- Add an entry if necessary, then click "Delete."
- You should be taken to a confirmation page: "Confirm deletion of
  EAN..."
- Confirm deletion and verify that the EAN was deleted.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>