and remove effectively unused m_aErrorHandlers

Change-Id: I7505d1d27ccbde2728c01c41ff91faa846429d7d
Reviewed-on: https://gerrit.libreoffice.org/52540Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>