availability zone list command shows nova redundantly

[Tetsuro Nakamura]

Description
===========
"openstack availability zone list" command shows nova redundantly.

Steps to reproduce
==================
1. install OpenStadk on devstack with default settings
2. type availability zone list command "$ openstack availability zone list"

Logs
==================

# admin user
$ openstack availability zone list
+-----------+-------------+
| Zone Name | Zone Status |
+-----------+-------------+
| internal | available |
| nova | available |
| nova | available |
| nova | available |
| nova | available |
+-----------+-------------+

$ nova availability-zone-list
+-----------------------+----------------------------------------+
| Name | Status |
+-----------------------+----------------------------------------+
| internal | available |
| |- vmcontroller | |
| | |- nova-conductor | enabled :-) 2017-08-02T08:33:14.000000 |
| | |- nova-scheduler | enabled :-) 2017-08-02T08:33:13.000000 |
| | |- nova-consoleauth | enabled :-) 2017-08-02T08:33:12.000000 |
| nova | available |
| |- vmcompute | |
| | |- nova-compute | enabled :-) 2017-08-02T08:33:14.000000 |
| |- vmcontroller | |
| | |- nova-compute | enabled :-) 2017-08-02T08:33:15.000000 |
+-----------------------+----------------------------------------+

# demo user
$ openstack availability zone list
+-----------+-------------+
| Zone Name | Zone Status |
+-----------+-------------+
| nova | available |
| nova | available |
| nova | available |
| nova | available |
+-----------+-------------+

$ nova availability-zone-list
+------+-----------+
| Name | Status |
+------+-----------+
| nova | available |
+------+-----------+

[Tetsuro Nakamura (tetsuro0907)]

Is this showing availability zone of nova, neutron, etc one time?
It is difficult to understand.