PathSettings::impl_storePath wants to be able to nil the Dictionaries
path in the old copy of properties

Change-Id: Id579914cfa8b459efce962d304e2f9d6185bd55f
Reviewed-on: https://gerrit.libreoffice.org/64115
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
(cherry picked from commit f913bdf7)
Reviewed-on: https://gerrit.libreoffice.org/64145