Allow snapshot name with null
According to cinder api schema [0],
snapshot name is allow null and minLength 0.
[0]:https://github.com/openstack/cinder/blob/master/cinder/api/schemas/snapshots.py#L29
Change-Id: I0d9e07fb1249d3daaed95520a8c771c083f5d54b
diff --git a/tempest/lib/api_schema/response/volume/snapshots.py b/tempest/lib/api_schema/response/volume/snapshots.py
index e9aeb64..9d52801 100644
--- a/tempest/lib/api_schema/response/volume/snapshots.py
+++ b/tempest/lib/api_schema/response/volume/snapshots.py
@@ -28,7 +28,7 @@
'status': {'type': 'string'},
'description': {'type': ['string', 'null']},
'created_at': parameter_types.date_time,
- 'name': {'type': 'string'},
+ 'name': {'type': ['string', 'null']},
'volume_id': {'type': 'string', 'format': 'uuid'},
'metadata': metadata,
'id': {'type': 'string', 'format': 'uuid'},