Fixes golang/go#14065

Change-Id: Ic19a0f740cddced8fb782f65cea14da383b047b1
Reviewed-on: https://go-review.googlesource.com/18802Reviewed-by: Olivier Poitrey <rs@rhapsodyk.net>
Reviewed-by: Daniel Morsing <daniel.morsing@gmail.com>
Reviewed-by: Chris Broadfoot <cbro@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>