Make etcd3 setup work with IPv6 addresses
Make etcd3 setup work with IPv6 addresses

The client are told to connect to SERVICE_HOST instead of HOST_IP, so
we need to start etcd3 with matching listening parameters.

Change-Id: I96389090180d21d25d72df8f9e8905b850bcaee9
Partial-Bug: 1656329

group-policy/devstack,dtroyer/devstack,nawawi/openstack,openstack-dev/devstack,noironetworks/devstack,noironetworks/devstack,nawawi/openstack,dtroyer/devstack,openstack-dev/devstack,group-policy/devstack