Change If1e03c9343b8cc9c34bd51c2b4d25acdb21131ff made the
"PUT /os-services/*" APIs only work with nova-compute services
since they now rely on finding the compute service in a cell
via the host_mappings record in the API database, and host
mappings only exist for compute services.
No one should have relied on disabling a non-compute service since
that does nothing, at least with in-tree code.
This change just adds a release note for awareness.
Change-Id: Idb5bbc31a0aabc328f11e5a9979e5b80651a8f67
Closes-Bug: #1700359