Fixes golang/go#25354

Change-Id: Ic74005ed26792a78354ffe76f567e9a009eabe9a
Reviewed-on: https://go-review.googlesource.com/112738
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>