Bug 24370: Don't reset library when editing a suggestion

Bug 24370: Don't reset library when editing a suggestion

When editing a suggestion, the library will be reset to the currently
logged in librarian's homebranch, no matter what the libray was before.

This fixes this, the library selection will remain at the db value when
edited.

To test:
- Create a suggestion with Any library.
- Edit the suggestion - it will show your homebranch as library
- Change to any library but your homebranch
- The summary should show the correct value after saving
- Edit the suggestoin again - it's set back to your homebranch again
- Apply patch
- Repeat the steps, the pull down should now show the correct library
  at all times.

Caveat: I think there is a somewhat separate issue/bug in that once a library
was saved, you cannot switch back to "Any". I haven't been able to fix this and
suggest to maybe file a separate bug.

Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>