Bug 13523 - AddBiblio fails on mysql with STRICT_TRANS_TABLES

Bug 13523 - AddBiblio fails on mysql with STRICT_TRANS_TABLES

This patch removes the NOT NULL restriction on biblioitems.marcxml and
deletedbiblioitems.marcxml due to STRICT_TRANS_TABLES default in
Mysql 5.6.22 and onwards.

Test:

1. check mysql global settings:
   mysql > SELECT @@GLOBAL.sql_mode;
   verify that STRICT_TRANS_TABLES is not set
2. set STRICT_TRANS_TABLES (or upgrade mysql to > 5.6.21)
   mysql > SET @@GLOBAL.sql_mode = 'STRICT_TRANS_TABLES';
3. try to add biblio in Cataloguing module
   verify that it fails with a "software error"
4. apply patch
5. repeat 3 and verify that there is no "software error" any more

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
I confirm with the problem with mariadb and STRICT_TRANS_TABLES enabled.
On adding a biblio (C4::Biblio::AddBiblio), biblioitems is populate in
_koha_add_biblioitem but marxcml is not generated yet. It's in
ModBiblioMarc, few lines later.
The NOT NULL condition is not valid here.

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
(cherry picked from commit 4b59bc4e2b591b32ff28eccda0baf8d131544736)
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>