gc: fix copy([]int, string) error message
gc: fix copy([]int, string) error message

R=rsc
CC=golang-dev
http://codereview.appspot.com/4433064

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

tav/go,tav/go,tav/go,tav/go,tav/go,tav/go,tav/go