Add required pool_id property to HealthMonitor

When I create a healthmonitor with a pool id by openstack sdk, there is an
error with the message "Failed to parse request. Required attribute
'pool_id' not specified", Then I find the code has no the parameter that
"pool_id".

I modify the healthmonitor class, I add a new line pool_id =
resource.Body('pool_id'), then successfully create a healthmonitor.

Change-Id: I95901152849341862333f1b3694c6265c43879ce
Closes-Bug: 1711546

openstack/network/v2/health_monitor.py

@@ -51,6 +51,8 @@ class HealthMonitor(resource.Resource):
     #: List of pools associated with this health monitor
     #: *Type: list of dicts which contain the pool IDs*
     pool_ids = resource.Body('pools', type=list)
+    #: The ID of the pool associated with this health monitor
+    pool_id = resource.Body('pool_id')
     #: The ID of the project this health monitor is associated with.
     project_id = resource.Body('tenant_id')
     #: The maximum number of seconds for a monitor to wait for a

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

@@ -23,6 +23,7 @@ EXAMPLE = {
     'id': IDENTIFIER,
     'max_retries': '6',
     'pools': [{'id': '7'}],
+    'pool_id': '7',
     'tenant_id': '8',
     'timeout': '9',
     'type': '10',
@@ -54,6 +55,7 @@ class TestHealthMonitor(testtools.TestCase):
         self.assertEqual(EXAMPLE['id'], sot.id)
         self.assertEqual(EXAMPLE['max_retries'], sot.max_retries)
         self.assertEqual(EXAMPLE['pools'], sot.pool_ids)
+        self.assertEqual(EXAMPLE['pool_id'], sot.pool_id)
         self.assertEqual(EXAMPLE['tenant_id'], sot.project_id)
         self.assertEqual(EXAMPLE['timeout'], sot.timeout)
         self.assertEqual(EXAMPLE['type'], sot.type)