YKD: Fix loading of YKD quorum module

Although YKD is currently unsupported, untested and decprecated it's
handy for testing things in the quorum module.

This patch allows YKD to actually load without an error. It does not fix
anything else in the service!

Also remove vsftype and its reference to YKD being the preferred and
default provider from the corosync.conf man page,
as that hasn't been true for a considerable time.

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