Fix rally "volume_type" parameter
Rally test create_snapshot_and_attach_volume
currently fails with:
"The parameter 'volume_type' is required
and should not be empty."
size:
min: 1
max: 1
+ volume_type: "test"
runner:
type: "constant"
times: 2
flavor:
name: "m1.tiny"
servers_per_tenant: 1
+ volume_types:
+ - "test"
api_versions:
cinder:
version: 2
