Add policy description for networks_associate

This commit adds policy doc for networks_associate policies.

Partial implement blueprint policy-docs

Change-Id: I7c38b068ca2264470a211f8121fdb55dede1fdfd

nova/policies/networks_associate.py

@@ -13,8 +13,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from oslo_policy import policy
-
 from nova.policies import base
 
 
@@ -22,9 +20,27 @@ BASE_POLICY_NAME = 'os_compute_api:os-networks-associate'
 
 
 networks_associate_policies = [
-    policy.RuleDefault(
-        name=BASE_POLICY_NAME,
-        check_str=base.RULE_ADMIN_API),
+    base.create_rule_default(
+        BASE_POLICY_NAME,
+        base.RULE_ADMIN_API,
+        """Associates and Disassociates a network from a host or project.
+
+These APIs are only available with nova-network which is deprecated.""",
+        [
+            {
+                'method': 'POST',
+                'path': '/os-networks/{network_id}/action (disassociate_host)'
+            },
+            {
+                'method': 'POST',
+                'path': '/os-networks/{network_id}/action'
+                        ' (disassociate_project)'
+            },
+            {
+                'method': 'POST',
+                'path': '/os-networks/{network_id}/action (associate_host)'
+            }
+        ]),
 ]