The option is saved in registrymodifications.xcu, not yet in the document.

(cherry picked from commit 0fc471e8218b53b8b9e505d2af3e015abf3910f3)

Change-Id: I6facc8d6e456046003f2c38ce79a1fcfc712d027
Reviewed-on: https://gerrit.libreoffice.org/67280
Tested-by: Jenkins
Reviewed-by: Eike Rathke <erack@redhat.com>