Bug 18725: (QA follow-up) Use make_column_dirty instead of status change

Bug 18725: (QA follow-up) Use make_column_dirty instead of status change

Moving the status to the invalid 'processing' might well have unwanted
side-effects. (The status column will be set to empty string and we have
a problem if it is not processed.)

This patch allows pass-through of DBIX's make_column_dirty in
Koha::Object (simple tests included) and uses it to force an update.
If the update does not return true, it still exits.

Test plan:
[1] Read the changes.
[2] Run t/db_dependent/Koha/Object.t

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Conflicts:
	Koha/Object.pm