sync version in "base" package
setup/dirs: don't include `(find-dll-dir)` in `(get-lib-search-dirs)`

I don't see a reason to include `(find-dll-dir)` in the result of
`(get-lib-search-dirs)`. It's practically always redundant, and
including it causes problems for sandboxes --- since `(find-dll-dir)`
must inspect the Racket executable on Windows and Mac OS X, and that
access is normally not allowed by a sandbox.