after we make dbaccess consistently use COLUMN_POSITION_NOT_FOUND

Change-Id: Ia22c17196e8d651201c04239505d28e54369a8a4
Reviewed-on: https://gerrit.libreoffice.org/46501Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>