Fixes #11805

Change-Id: I081e16b869dc706bd847ee645bb902bc671c123f
Reviewed-on: https://go-review.googlesource.com/12485Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>