cmd/go: fix 'go help <command>'
cmd/go: fix 'go help <command>'

It depended on the old behavior of functions in structs.

R=golang-dev, rsc
CC=golang-dev, r
http://codereview.appspot.com/5656076

Committer: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang