ever since
   commit 84a3db80
   Date:   Mon Sep 18 23:08:29 2000 +0000
   initial import

where it could insert an uninitialised pointer into the
SwGlblDocContents sorted vector

Change-Id: Id58778444593c39b5f80bac3a6dab8e14404030a
Reviewed-on: https://gerrit.libreoffice.org/59932
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>