DEICH-6311 koha: fix Deichman::Item::AvailableItemsCount
As it was, it always returned the number 1 (= number of rows), but what we want is the actual count from the SQL query.
Closes DEICH-6311
As it was, it always returned the number 1 (= number of rows), but what we want is the actual count from the SQL query.
Closes DEICH-6311