This CL expands the job of "dist bootstrap" to be "finish make.bash".
I need to change that logic in upcoming CLs related to cmd/go
changes, and I'd rather not change it in three places in three different
shell script languages.

Change-Id: I545dc215e408289e4d0b28f7c2ffcd849d89ad3b
Reviewed-on: https://go-review.googlesource.com/72870Reviewed-by: David Crawshaw <crawshaw@golang.org>