As the folloing content of etc/nova/api-paste.ini, legacy v2
endpoint is /v2, not /v2.1.
/v1.1: openstack_compute_api_v21_legacy_v2_compatible
/v2: openstack_compute_api_v21_legacy_v2_compatible
/v2.1: openstack_compute_api_v21
So this patch fixes the endpoint.
Partially implements blueprint complete-todo-in-api-concept-doc
Change-Id: I6d9346ced38f522c516778cadae217d1d5c9cff1