Use correct terminology for subnets

OpenStack uses 'CIDR' incorrectly in many places.  We are not going
to perpetuate that usage.  The correct name here is simply 'subnet'
as the data is the network address for the subnet, in CIDR notation.

Also, some additional cleanups as suggested in comments to
https://review.openstack.org/#/c/84782

Depends-on: I3c0748074a6511ff92500516b3129886d2476eed
Change-Id: Ib44c49dc1739ce7d881432e482dd16f8928eef49

doc/source/commands.rst

@@ -116,7 +116,7 @@ referring to both Compute and Volume quotas.
 * ``service``: (**Identity**) a cloud service
 * ``service provider``: (**Identity**) a resource that consumes assertions from an ``identity provider``
 * ``snapshot``: (**Volume**) a point-in-time copy of a volume
-* ``subnet``: (**Network**) - a pool of private IP addresses that can be assigned to instances or other resources
+* ``subnet``: (**Network**) - a contiguous range of IP addresses assigned to a network
 * ``token``: (**Identity**) a bearer token managed by Identity service
 * ``usage``: (**Compute**) display host resources being consumed
 * ``user``: (**Identity**) individual cloud resources users

openstackclient/network/v2/subnet.py

@@ -53,10 +53,10 @@ class ListSubnet(lister.Lister):
 
         data = self.app.client_manager.network.subnets()
 
-        headers = ('ID', 'Name', 'Network', 'CIDR')
+        headers = ('ID', 'Name', 'Network', 'Subnet')
         columns = ('id', 'name', 'network_id', 'cidr')
         if parsed_args.long:
-            headers += ('Project', 'DHCP', 'DNS Nameservers',
+            headers += ('Project', 'DHCP', 'Name Servers',
                         'Allocation Pools', 'Host Routes', 'IP Version',
                         'Gateway')
             columns += ('tenant_id', 'enable_dhcp', 'dns_nameservers',

openstackclient/tests/network/v2/test_subnet.py

@@ -34,12 +34,12 @@ class TestListSubnet(TestSubnet):
         'ID',
         'Name',
         'Network',
-        'CIDR'
+        'Subnet'
     )
     columns_long = columns + (
         'Project',
         'DHCP',
-        'DNS Nameservers',
+        'Name Servers',
         'Allocation Pools',
         'Host Routes',
         'IP Version',