Follow-up to CL 38446.

Passes toolstash-check -all.

Change-Id: I04cadc058cbaa5f396136502c574e5a395a33276
Reviewed-on: https://go-review.googlesource.com/38669
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>