Passes toolstash -cmp.

Change-Id: Ia497b51c74a9c760a873e1ed690e4408fd0fe596
Reviewed-on: https://go-review.googlesource.com/19844Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>