Bifrost cannot modify /etc/hosts from within a container, so add a
host entry during bootstrap.
This was previously fixed by Ied378b4dd755788e75ad1814cecb5700732ba83e
but the logic in bifrost was changed [1], making it out of sync with
kolla-ansible, and triggering a write to /etc/hosts. This change applies
the new logic in bifrost to kolla-ansible, ensuring that the file will
not need to change in the container.
Longer term we should look at ways to make bifrost less eager to modify
/etc/hosts, accepting any file that will work for RabbitMQ.
[1]
60b9a9917e
Change-Id: I0ee05feae3630435b2ec52cfeddf33647a974ee0
Closes-Bug: #1661009
376c607f37