and use "using" statements for the places where the overrides were
resolving ambiguities

Change-Id: Icb1d1a41f19e00f28a19947aa2c40bd5778fff94
Reviewed-on: https://gerrit.libreoffice.org/52993Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>