allow release info change on apt update
allow release info change on apt update

debian buster changed from stable to oldstable, without this change
apt-get update fails to run on old systems.

Change-Id: I6527d2c0c361c03cbb6fc43aa3a03896894fb8e1

openstack/openstack-ansible-lxc_hosts,openstack/openstack-ansible-lxc_hosts