The result was that t/deps/dirtest was actually failing in some cases. But
it wasn't failing quite reliably enough, because the failing test was
dirtest/dir1/all, which has the same name as some other 'all' files,
confusing the issue. Renamed dirtest/dir1/all.do to dirtest/dir1/go.do instead.
Reported by Prakhar Goel and Berke Durak.
It actually decreases readability of the .do files - by not making it
explicit when you're going into a subdir.
Plus it adds ambiguity: what if there's a dirname.do *and* a dirname/all?
We could resolve the ambiguity if we wanted, but that adds more code, while
taking out this special case makes *less* code and improves readability.
I think it's the right way to go.
We had a bug (fixed in the previous commit) where doing 'redo-ifchange
dirname' (which runs dirname/all.do) would not create the stamp correctly,
so that it would always show up as dirty.
It's a little bit complicated to simulate, but this does it.
