make that variable protected again

Change-Id: I17235397e490458c250165c36bec97bf1ce326d7
Reviewed-on: https://gerrit.libreoffice.org/9721
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>