[Aboriginal] Migrating aboriginal->mkroot list.

[Rob Landley]

I'm going to try to get a second mkroot release out this weekend, and as part of
that I'm shutting down the old aboriginal list and migrating the subscribers
here to the mkroot list.

It's not a hugely high volume project, but if nobody defends and regression
tests "simple" we wind up with this sort of nonsense:

  https://twitter.com/landley/status/964620648050982912

And then I have to clean up after it and fight to get back to where we _were_.

FYI,

Rob