net: fix typo
net: fix typo

Fixes issue 819.

R=rsc
CC=golang-dev
http://codereview.appspot.com/1421041

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