Follow the convertion (https://golang.org/s/generatedcode) for generated
code.

Change-Id: If06c4d5c3974a163ff75a9acc7141292eb43b7ef
Reviewed-on: https://go-review.googlesource.com/118818
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>