extend-node-status

add 'disabled_reason' filed into 'ComputeNode' resource, to distinguish
which nodes are disabled by Watcher and which are not by Watcher.

Implements:blueprint extend-node-status

Change-Id: I7175f14870834a4582e45309529d7e8d9fbb2e6f

watcher/tests/decision_engine/cluster/test_nova_cdmc.py

@@ -37,7 +37,13 @@ class TestNovaClusterDataModelCollector(base.TestCase):
         m_nova_helper = mock.Mock(name="nova_helper")
         m_nova_helper_cls.return_value = m_nova_helper
         m_nova_helper.get_service.return_value = mock.Mock(
-            host="test_hostname")
+            id=1355,
+            host='test_hostname',
+            binary='nova-compute',
+            status='enabled',
+            state='up',
+            disabled_reason='',
+        )
 
         fake_compute_node = mock.Mock(
             id=1337,