Found this while reading through the code. The benchmark
accidently called the wrong function.

Change-Id: Idb88aa71e7098a4e29e7f5f39e64f8c5f8936a2a
Reviewed-on: https://go-review.googlesource.com/19977Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>