Remove redundant flag.Usage code

(thanks to Uriel on #go-nuts)

geodns.go

@@ -17,10 +17,6 @@ func main() {
 
 	log.SetPrefix("geodns ")
 	log.SetFlags(log.Lmicroseconds | log.Lshortfile)
-
-	flag.Usage = func() {
-		flag.PrintDefaults()
-	}
 	flag.Parse()
 
 	dirName := "dns"