Passes toolstash -cmp.

Change-Id: I4a72e3e130c38868ee8ecef32cad58748aa5be52
Reviewed-on: https://go-review.googlesource.com/36353Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>