net: fix botched cgo netbsd merge
net: fix botched cgo netbsd merge

Fix botched cgo_netbsd.go merge and remove redundant +build directive.

R=golang-dev, rsc
CC=golang-dev
http://codereview.appspot.com/6282048

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang