unicode/norm: remove unreachable code Makes vet happy. Change-Id: Idbebf963fafeae99c1304094927e74af4b30176a Reviewed-on: https://go-review.googlesource.com/31757 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>