Re-importing the path probably breaks other stuff.  Anyway, we only have one
overlay now so this short/simpler thing works.

Rely on upstream package to supply typing and challenge-bypass-ristretto as
necessary.  Simplify our expression (approximately pointfree style) so we
don't have to know about any other arguments that might be passed or accepted.

I don't know

When it changes we often have to rebuild ghc ... :(

Also configure a new value on the staging grid

This removes the code that might delete a Tahoe-LAFS nodedir and replaces it
with code that will try to save an unexpected copy of it out of the way
instead.