Found by github.com/mvdan/unparam.

Change-Id: I5a6664cceeba1cf1c2f3236ddf4db5ce7a64b02a
Reviewed-on: https://go-review.googlesource.com/37835Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>