add command "openstack rbac list"

[ting.wang]

This bug aim to explain how I plan to implement command 'openstack rbac list' which is a part of the bp[1].

With command "neutron rbac-list"[2], we can get the rbac information from Neutron.
But in openstackclient, we have not implemented this command yet.So,add it.

$neutron rbac-list
+--------------------------------------+-------------+--------------------------------------+
| id | object_type | object_id |
+--------------------------------------+-------------+--------------------------------------+
| 374f5ea8-9be3-4f34-a78f-450a5e275228 | network | a6511829-3e2b-4001-b457-7c223a04b20b |
| f1af9230-a959-4e4d-8e35-6c7c1b1e88c2 | network | f9d3460e-22a6-4ae2-8705-83ebafdcc0da |
+--------------------------------------+-------------+--------------------------------------+

In neutronclient, there are not any optional arguments in command 'rbac-list' although the response looks like this:
RESP BODY: {"rbac_policies": [{"target_tenant": "*", "tenant_id": "82c2afcd955e4b28ab8825ef2a61074c", "object_type": "network", "object_id": "a6511829-3e2b-4001-b457-7c223a04b20b", "action": "access_as_external", "id": "374f5ea8-9be3-4f34-a78f-450a5e275228"}, {"target_tenant": "c45eb3a281d34e3e8fa7c2809fad7a25", "tenant_id": "82c2afcd955e4b28ab8825ef2a61074c", "object_type": "network", "object_id": "f9d3460e-22a6-4ae2-8705-83ebafdcc0da", "action": "access_as_shared", "id": "f1af9230-a959-4e4d-8e35-6c7c1b1e88c2"}]}

The other arguments like "target_tenant" will be displayed when we execute command "neutron rbac show ***".

Similarly, executing command "openstack rbac list" will return result like this:
$ openstack rbac list
+--------------------------------------+-------------+--------------------------------------+
| ID | Object_type | Object_id |
+--------------------------------------+-------------+--------------------------------------+
| 374f5ea8-9be3-4f34-a78f-450a5e275228 | network | a6511829-3e2b-4001-b457-7c223a04b20b |
| f1af9230-a959-4e4d-8e35-6c7c1b1e88c2 | network | f9d3460e-22a6-4ae2-8705-83ebafdcc0da |
+--------------------------------------+-------------+--------------------------------------+
and no optional arguments supplied.

ref:
[1]bp:
https://blueprints.launchpad.net/python-openstackclient/+spec/neutron-client-rbac
[2]about rbac in neutron:
https://developer.rackspace.com/blog/A-First-Look-at-RBAC-in-the-Liberty-Release-of-Neutron/

[Richard Theis (rtheis)]

You can close this bug and track the work under the blueprint.