They are unused, and vet wants them to have
a function prototype.

Updates #11041

Change-Id: Idedc96ddd3c3cf1b1d2ab6d98796367eab29f032
Reviewed-on: https://go-review.googlesource.com/27492
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>