Add subnet_id property for FloatingIP

In openstackclient we can pass a "subnet_id" param while creating
floatingip, but missing in FloatingIP properties.

Change-Id: I5c2b93d7e737755958ff074f3a84e592c94f0fe2
Closes-Bug: #1733258

openstack/network/v2/floating_ip.py

@@ -30,8 +30,9 @@ class FloatingIP(resource.Resource):
     allow_list = True
 
     _query_mapping = resource.QueryParameters(
-        'description', 'fixed_ip_address', 'floating_ip_address',
-        'floating_network_id', 'port_id', 'router_id', 'status',
+        'description', 'fixed_ip_address',
+        'floating_ip_address', 'floating_network_id',
+        'port_id', 'router_id', 'status', 'subnet_id',
         project_id='tenant_id')
 
     # Properties
@@ -65,6 +66,8 @@ class FloatingIP(resource.Resource):
     status = resource.Body('status')
     #: Timestamp at which the floating IP was last updated.
     updated_at = resource.Body('updated_at')
+    #: The Subnet ID associated with the floating IP.
+    subnet_id = resource.Body('subnet_id')
 
     @classmethod
     def find_available(cls, session):

openstack/tests/unit/network/v2/test_floating_ip.py

@@ -29,6 +29,7 @@ EXAMPLE = {
     'status': 'ACTIVE',
     'revision_number': 12,
     'updated_at': '13',
+    'subnet_id': '14'
 }
 
 
@@ -62,6 +63,7 @@ class TestFloatingIP(testtools.TestCase):
         self.assertEqual(EXAMPLE['status'], sot.status)
         self.assertEqual(EXAMPLE['revision_number'], sot.revision_number)
         self.assertEqual(EXAMPLE['updated_at'], sot.updated_at)
+        self.assertEqual(EXAMPLE['subnet_id'], sot.subnet_id)
 
     def test_find_available(self):
         mock_session = mock.Mock()