cfg: Reinstate cfg tracking

cfg: Reinstate cfg tracking

CFG tracking was removed in 815375411e80131f31b172d7c43625769ee8b53d,
probably as a mistake, as part of the tidy up of cfg and the removal of
dynamic loading. This means that shutdown tracking (using
cfg_try_shutdown()) stopped working.

This patch restores the trackstart & trackstop API calls (renamed to be
more consistent with the exiting libraries) so that shutdown tracking
can be used again.

Change cfg.shutdown_timeout to be in milliseconds rather than seconds
nd use libqb macros for conversion.

Add --force option to corosync-cfgtool -H

Signed-off-by: Christine Caulfield <ccaulfie@redhat.com>
Reviewed-by: Jan Friesse <jfriesse@redhat.com>