When extending an existing sub-resource definition, the
SUB_RESOURCE_ATTRIBUTE_MAP must define the extended resources/attributes
under the 'parameters' object. This instructs the API internals to
update the existing sub-resource's attribute map rather than just
overwrite it. For internals see the logic in the extend_resources()
method in neutron.api.extensions [1]. For example the
qos_bw_limit_direction in neutron uses this approach for its
BANDWIDTH_LIMIT_RULES definition (also see related lib commit
I823f567ddf9c895eb3cf94e95ae34a382d67f51d).
This patch adds that support to the base api def test case and also
updates the contributor internals to document such. No release note
included since nothing changed from a consumption perspective.
[1] https://github.com/openstack/neutron/blob/master/neutron/api/extensions.py#L350
Change-Id: Ib91004490dc3ca71b7caafe5cc3cb07417be1e4c
36bb16b941