CL 124135 follow-ups.

Change-Id: Ib7e2066bd2d18851561e03386709a1b42b50fcef
Reviewed-on: https://go-review.googlesource.com/124136Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Andrew Bonventre <andybons@golang.org>