I'm a bit confused. Weren't we shooting for parity with the old c10n behavior? The pre-waldon-refactor script would be ok with nil user-data and still call out to the c10n service.

https://github.com/coreos/init/blob/e6584f44ffd9b23fac0a99771dd63fa2b201da71/bin/coreos-c10n#L19