Bug 15730 - 500 error on returns.pl if barcode doesn't exist

Bug 15730 - 500 error on returns.pl if barcode doesn't exist

If a librarian enters a barcode that does not match an item in the
database, a 500 error will be displayed instead of the "No item with
barcode" message.

Test Plan:
1) Enter an invalid barcode on returns.pl
2) Note the 500 error
3) Apply this patch
4) Repeat setp 1
5) Note the "No item with barcode" message

Signed-off-by: Aleisha <aleishaamohia@hotmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com