Bug 21463: (bug 18789 follow-up) Fix library display on the overdue list view

Bug 21463: (bug 18789 follow-up) Fix library display on the overdue list view

branchcode is no longer retrieved from the SQL query, we should use the
Koha::Patron object instead.

Test plan:
Create some overdues and list them on Home › Circulation › Overdues
=> With this patch applied you should see that the "Library" column is
correctly filled with the patron's library name

Signed-off-by: Pierre-Marc Thibault <pierre-marc.thibault@inLibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>