gofmt: simplify "x, _ = range y" to "x = range y"
gofmt: simplify "x, _ = range y" to "x = range y"

(inspired by CL 3529041 by hitchmanr@gmail.com)

R=rsc
CC=golang-dev
http://codereview.appspot.com/3527042

Committer: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

wesolows/golang,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,wesolows/golang-old,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old