This disallows changing mbAuto and changing values of
ImplSchedulerData outside of Scheduler / Task functions.

Change-Id: Ia624999bd63190c072eb66427aec38e7ac8cfa1b
Reviewed-on: https://gerrit.libreoffice.org/33317Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>