This was broken in https://golang.org/cl/36255

Change-Id: Ib23323a745a650ac51b0ead161076f97efe6d7b7
Reviewed-on: https://go-review.googlesource.com/36543
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>