cmd/go-contrib-init: fix in-GOPATH check
cmd/go-contrib-init: fix in-GOPATH check

It's okay to have GOROOT=$HOME/go, GOPATH=$HOME.

That's what I have.

It's just not okay to hack in Go under $GOPATH/src.

Change-Id: I6ae69aceb43970bbdc9631ab090689a153954087
Reviewed-on: https://go-review.googlesource.com/45651
Reviewed-by: Steve Francia <97224216d9b4001d2da5fac1d1d534510be40bbe@golang.org>

syreclabs/go-tools,syreclabs/go-tools,golang/tools,syreclabs/go-tools,golang/tools,golang/tools,golang/tools,syreclabs/go-tools,syreclabs/go-tools,syreclabs/go-tools,golang/tools