Bug 21869: Fix incorrect value setting in DB update

Bug 21869: Fix incorrect value setting in DB update

To test:
1 - Set some value for MarkLostAsReturned syspref
2 - Set your db version to 17.12.00.035 (or load an older db)
3 - updatedatabase
4 - Note your values are lost and db is incorrectly set
5 - Apply patch
6 - Reset values
7 - Reset DB version
8 - Run updatedatabase
9 - Original values are retained

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>