cgo: fix incorrect print found by govet
cgo: fix incorrect print found by govet

R=golang-dev
CC=golang-dev
http://codereview.appspot.com/5445052

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go