Passes toolstash/buildall.

Change-Id: I928a2ef39fb10091957f35bb3f1564498f6f1b83
Reviewed-on: https://go-review.googlesource.com/30312
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>