sudo.bash: diagnose when the go tool is not in $PATH Fixes issue 4386.
sudo.bash: diagnose when the go tool is not in $PATH
Fixes issue 4386.

R=golang-dev, iant
CC=golang-dev
http://codereview.appspot.com/6854050

tv42/old-go,pombredanne/go-deleteme,dsriram/golang,pombredanne/go-deleteme,gnanderson/go,gnanderson/go,gnanderson/go,dsriram/golang,pombredanne/go-deleteme,apparentlymart/golang,pombredanne/go-deleteme,apparentlymart/golang,tv42/old-go,apparentlymart/golang,apparentlymart/golang,dsriram/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,dsriram/golang,apparentlymart/golang,gnanderson/go,dsriram/golang,pombredanne/go-deleteme,apparentlymart/golang,apparentlymart/golang,tv42/old-go,tv42/old-go,tv42/old-go,tv42/old-go,dsriram/golang,gnanderson/go,tv42/old-go,dsriram/golang,gnanderson/go,gnanderson/go