route: fill correctly field

https://github.com/golang/net/blob/master/route/address.go#L37-L56

Wrong order of filling the buffer

Change-Id: Ia598a1f9aaba03f1c0e9890bcf48ed097eb0a1e6
GitHub-Last-Rev: 1ed3d11bbd87fa4f0aeed840ba3be29e504354fd
GitHub-Pull-Request: golang/net#60
Reviewed-on: https://go-review.googlesource.com/c/net/+/213117
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

route/address.go

@@ -46,12 +46,12 @@ func (a *LinkAddr) marshal(b []byte) (int, error) {
 	data := b[8:]
 	if nlen > 0 {
 		b[5] = byte(nlen)
-		copy(data[:nlen], a.Addr)
+		copy(data[:nlen], a.Name)
 		data = data[nlen:]
 	}
 	if alen > 0 {
 		b[6] = byte(alen)
-		copy(data[:alen], a.Name)
+		copy(data[:alen], a.Addr)
 		data = data[alen:]
 	}
 	return ll, nil