Try to run `cl info -v spec` against a remote host. This will fail because `head` is not defined on `RemoteBundleClient`. When modifying the client API, I think that the pattern is:
- Add method to client\bundle_client\BundleClient
- Implement new method in client\local_bundle_client\LocalBundleClient
- Register method in client\remote_bundle_client\RemoteBundleClient. In this case, add name (`head`) to `CLIENT_COMMANDS`.