Revert "use nash for cue"

This reverts commit f691d25bd23716e9411288d3eb9bd4c9b9d33ae1.

Oddly, this causes a failure to boot, on some linux, for some reason
heretofore unknown to medical science.
Merge branch 'master' of https://github.com/urbit/urbit
fixing bug in partially merged unix.c