No functional changes.

Change-Id: I0842b2560f4296abfc453410fdd79514132cab83
Reviewed-on: https://go-review.googlesource.com/31935
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>