can't find an easy way of removing the duplication, even though
that BeginLocking() stuff looks ripe for simplification.

Change-Id: I97b580b3668381c12b62136ea09772d91ab11eac
Reviewed-on: https://gerrit.libreoffice.org/44884Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>