Currently OS_ENDPOINT_TYPE and --os-interface are being ignored for
network commands. This means the public URL is always used.
Make sure that these are picked up correctly so we hit the correct
endpoint (internal/admin/etc.) for commands such as:
$ openstack --os-interface internal network list
Change-Id: Iac05204e3056e386d84d3644b5da1a2bb322bb0a
Closes-bug: 1592368