Bug 20889: Prevent not for loan items to be checked out

Bug 20889: Prevent not for loan items to be checked out

1. Item type defined at item level (item-level_itypes=1)
2. Mark an item type not for loan (itemtypes.notforloan=1)
3. Checkout an item using this item type (items.itype="BK" for instance)
=> Checkout is not blocked!

I suspect
  commit 3953fdb921d7f280ffbaca813956357aa67d42ca
  Bug 19943: Remove itemtype vs itype confusion in CanBookBeIssued
to be the root of this issue.
One occurrence of $item->{itemtype} has not been replaced.
In this case it refers to the biblioitem->{itemtype} value whereas we want to use
$item->{itype}. So this issue does not happen if items.itype==biblioitem.itemtype
(just in case you are not reproducing the problem).

Test plan:
Make sure not for loan items cannot be checked out

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>