Add response parameters for quota_server_group ext

quota_server_group extension has been implemented since Juno, and
the extension adds server_group_members and server_groups parameters
to a response of quota API.
This patch adds them into the schema of quota API.

Change-Id: Ia11c6ced26aec4177ac98d32854da67f0604f976
diff --git a/tempest/api_schema/response/compute/quotas.py b/tempest/api_schema/response/compute/quotas.py
index f49771e..863104c 100644
--- a/tempest/api_schema/response/compute/quotas.py
+++ b/tempest/api_schema/response/compute/quotas.py
@@ -28,8 +28,13 @@
                     'metadata_items': {'type': 'integer'},
                     'key_pairs': {'type': 'integer'},
                     'security_groups': {'type': 'integer'},
-                    'security_group_rules': {'type': 'integer'}
+                    'security_group_rules': {'type': 'integer'},
+                    'server_group_members': {'type': 'integer'},
+                    'server_groups': {'type': 'integer'},
                 },
+                # NOTE: server_group_members and server_groups are represented
+                # when enabling quota_server_group extension. So they should
+                # not be required.
                 'required': ['instances', 'cores', 'ram',
                              'floating_ips', 'fixed_ips',
                              'metadata_items', 'key_pairs',