fakeVolumeHost previously implemented both the KubeletVolumeHost and
AttachDetachVolumeHost interfaces. This design makes it difficult to test the
CSIAttacher since it behaves differently depending on what type of
VolumeHost is supplied.
* Rename const for topology.../zone
* Rename const for topology.../region
* Rename const for failure-domain.../zone
* Rename const for failure-domain.../region
* Restore old names for compat