Bug 12122: TransferSlip should accept both itemnumber and barcode

Bug 12122: TransferSlip should accept both itemnumber and barcode

Added small patch to allow barcode as input in TransferSlip routine, mostly
to allow generating transfer slips where only barcode is present (aka.
javascript).

Test plan:
1) find book with <barcode> and <itemnumber>
2) generate transferslips with both:
  transfer-slip.pl?transferitem=<itemnumber>3967925&amp;branchcode=MPL&amp;op=slip
  transfer-slip.pl?barcode=<barcode>&amp;branchcode=MPL&amp;op=slip
and verify that the generated slips match.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Edit:
 - Added tests in t/db_dependent/Circulation_transfers.t

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Passes tests and QA script.
Works with both itemnumber or barcode as described.
Tested printing transfer slips with the URL examples given
and in the UI.