Bug 19828: Make Koha::Object->store translate DBIC exceptions into Koha exceptions

Bug 19828: Make Koha::Object->store translate DBIC exceptions into Koha exceptions

This patch introduces a try/catch block in store() and parses the error
when an exceptional situation takes place.

It only deals with FK constraint violations and duplicate IDs. The rest of the DBIC exceptions
are rethrown.

To test:

- Apply this patch
- Run:
  $ kshell
 k$ prove t/db_dependent/Koha/Object.t
=> SUCCESS: Tests pass!
- Sign off :-D

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>