Bug 24672: (bug 24430 follow-up) Do not get active orders on deleted biblio record

Bug 24672: (bug 24430 follow-up) Do not get active orders on deleted biblio record

On bug 24430 we replaced the call to CountBiblioInOrders with
Koha::Biblio->active_orders
In case the bibliographic record is deleted, the count must be set to 0.

This prevent the app to crash with:
Can't call method "active_orders" on an undefined value at
/home/vagrant/kohaclone/acqui/parcel.pl line 244

Test plan:
Create 2+ orders
Receive one, delete it, delete the bibliographic record
Receive the order one
=> Without this patch, on the parcel page you should get the error
=> With this patch applied you must be allowed to finish the receive

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>