Bug 29114: Trim whitespace before the barcode

Bug 29114: Trim whitespace before the barcode

The solution was to add regexp that trims all whitespaces.

How to test:
1. Go to the koha/virtualshelves/shelves.pl;
2. Add new list or edit existing one;
3. Start adding new items;
4. In the "Barcode" field add barcode(s) with whitespaces before them;
5. Observe that it wasn't added as the barcode isn't recognized because of whitespaces;
6. Apply the patch;
7. Repeat step 4;
8. Observe that the item was successfully added;

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