fields that are only referenced in the constructor

Change-Id: I44bddb2dce2f30c21ea0f1ada4c1615c854d3334
Reviewed-on: https://gerrit.libreoffice.org/54823Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>