Fixes golang/go#17424 Change-Id: I49d6e475c173da6a31542931d555ab87cc45a1c6 Reviewed-on: https://go-review.googlesource.com/30971 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Adam Langley <agl@golang.org>