like the other smart pointer types

Change-Id: I3ac1888c84fc1411cdfc3357b005afbb3b7d8bbe
Reviewed-on: https://gerrit.libreoffice.org/65926Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>