Allow a non-127.0.0.1 definition for the hostname.
Allow a non-127.0.0.1 definition for the hostname.

In some environments it might be useful to resolve the hostname to
an IP address that is reachable by other hosts in the local network.
If some of the configuration scripts have taken care of putting
a proper line in /etc/hosts, do not try to override it by appending
a 127.0.0.1 one.

Change-Id: I7ae20a66c473b0c683803cc44654cd95fcce3639
Closes-Bug: 1746751

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