Since Yoga release we've wrongly have dropped hosts file refresh task
This task is still required, as despite /etc/hosts now are fully provisioned
on new computes, it still does not make old ones to recognize new
ones.
[1] 8cd65feae2
Depends-On: https://review.opendev.org/c/openstack/openstack-ansible-openstack_hosts/+/877824
Change-Id: I494caa4a4104129781159ea924f3aeae94dad9a8