and update sallogareas plugin to enforce this

Change-Id: Id0782c8a1f619372e10d931aec3c6a4743a4c86a
Reviewed-on: https://gerrit.libreoffice.org/52249Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>