In a new 1.3 microversion, the GET /resource_providers handler gains
support for a new query parameter 'member_of' which takes a value of
'in:' and a comma separated list of aggregate uuids, or a single
aggregate uuid.
The response is the list of resource providers that are associated
with any of those aggregates, or an empty list if there are none.
If in an old microversion, the query parameter is not accepted and a
400 is returned.
Change-Id: I82fc2003ce85dcadfecfea506e7d4adb47258c7a
8e797aad7c