we no longer have any experimental features depending on ca derivations,
so we can start removing them. since ca derivations are very invasive we
will need a while to remove all of the explicitly experimental code, and
even then we will not have removed *all* code related to ca derivations.
especially in the derivation goals there is a lot of code that is not as
easy to disentangle from experimental features as some would have hoped.
Change-Id: Ia456aadc6164613ded343f571318494d9310a549
eldritch horrors
dad28eca75