Bug 19974: Marking an item as 'lost' in additem.pl will not modify the current item

Bug 19974: Marking an item as 'lost' in additem.pl will not modify the current item

    TEST PLAN:

    1) Log in with your superlibrarian account
    2) Borrow any book
    3) Visit your Checkouts page, and click 'Show Checkouts'
    4) Click on the item's barcode to visit the item's page
    5) On the item's page, click the 'Edit' button, and choose 'Edit items'
    6) In the items table, click the 'Actions->Edit' button of the item you borrowed
    7) Mark that item as lost (it should be the first row of the form) and click the button 'Save changes'
    8) Visit your Checkouts page. The item should still be there, despite BZ12363 claiming it should've been automagically returned
        8.1) Your koha-log should also output a warning message: 'DBIx::Class::Storage::DBI::select_single(): Query returned more than one row...'
        8.2) If you visit the item's page, the modification had no effect. It should not be marked as lost.
    9) APPLY PATCH
    10) Start back from step 2), but this time, after marking the item as lost, the item's page should
        reflect the change, and the item you borrowed should've been automatically returned to the library

Signed-off-by: Jean-Manuel Broust <jean-manuel.broust@univ-lyon2.fr>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Amended: Using $item->{itemnumber} instead of new variable.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>