Found by github.com/mvdan/unparam.

Change-Id: I4795dd0221784d10cf7c9f7b84ea00787d5789f2
Reviewed-on: https://go-review.googlesource.com/37892Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>