When the etcd key tracking realms is first created the action is create, not set.

test/test_buildman.py

@@ -127,7 +127,7 @@ class TestEphemeral(unittest.TestCase):
     self.assertEqual(self.register_component_callback.call_count, 0)
 
     realm_created = Mock(spec=etcd.EtcdResult)
-    realm_created.action = EtcdAction.SET
+    realm_created.action = EtcdAction.CREATE
     realm_created.key = os.path.join(ETCD_REALM_PREFIX, REALM_ID)
     realm_created.value = json.dumps({
         'realm': REALM_ID,