Update announce self workaround opt description
Update announce self workaround opt description

This updates the announce self workaround config opt
description to include info about instance being set
as tainted by libvirt.

Change-Id: I8140c8fe592dd54fc09a9510723892806db49a56

openstack/nova,openstack/nova,mahak/nova,mahak/nova,mahak/nova,openstack/nova