In a mixed cluster, such as during a rolling upgrade, older nodes that do not implement `get_max_local_vnodeq` will return `{badrpc, _}` that will match this clause but return unexpected values.

We should either validate that we don't get back any unexpected values, change `get_max_local_vnodeq` to return something like `{ok, VMax}` that we can match on, or make the entire AAE throttling code path guarded by a new capbility -- and not use any of the new stuff until after the capability is active.