Fixes #11671

Change-Id: Ide1f8d92637dad2a2faed391329f9b6001789b76
Reviewed-on: https://go-review.googlesource.com/14742Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>