Bug 20446: Fix Edifact quotes processing

Bug 20446: Fix Edifact quotes processing

Caused by
  commit 04aea91de0f2fe1103e4021f880d135da1fd11a9
  Bug 15685: (QA follow-up) Address QA issues

->find is called on Koha::Object instead of the set class (Koha::Objects)
and raises the following error:
Can't use string ("Koha::Acquisition::Basket") as a HASH ref while
"strict refs" in use at /usr/share/koha/lib/Koha/Object.pm line 275.

This patch also makes sure $basketno refers to an existing basket in DB

I cannot provide a test plan, I have no idea how this code is used.

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>