Bug 8367: Make database update idempotent (across different MariaDB versions)

Bug 8367: Make database update idempotent (across different MariaDB versions)

The previous query seemed to work on MariaDB 10.1.48 (used by koha-testing-docker),
but it didn't work on MariaDB 10.3.29 (default in Debian 10 as of this writing),
but this patched query works on both indempotently.

Signed-off-by: Emmi Takkinen <emmi.takkinen@koha-suomi.fi>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Kelly <kelly@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kelly <kelly@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>