This is minor cleanup that reduces test output noise.

Change-Id: Ib6db4daf8cb67b7784b2d5b222fa37c7f78a6a04
Reviewed-on: https://go-review.googlesource.com/19997Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>