regression from
    commit f4ea84ff
    Date:   Thu Apr 25 16:35:14 2019 +0200
    tdf#119650 slow saving spreadsheet with comments, part 1

Change-Id: I91b3c009fb8b6739e98537de227ab563828b9c80
Reviewed-on: https://gerrit.libreoffice.org/72842
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>