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

Change-Id: I27899b24366d5c0d2c5574b5eaf3d7e0babc8909
Reviewed-on: https://go-review.googlesource.com/118820
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>