syscall: fix marshaling of stat messages on Plan 9

The order of the Qid fields was reversed. Mea culpa.

R=seed
CC=golang-dev
https://golang.org/cl/7231062

src/pkg/syscall/dir_plan9.go

@@ -68,9 +68,9 @@ func (d *Dir) Marshal(b []byte) (n int, err error) {
 	b = pbit16(b, uint16(n)-2)
 	b = pbit16(b, d.Type)
 	b = pbit32(b, d.Dev)
-	b = pbit64(b, d.Qid.Path)
-	b = pbit32(b, d.Qid.Vers)
 	b = pbit8(b, d.Qid.Type)
+	b = pbit32(b, d.Qid.Vers)
+	b = pbit64(b, d.Qid.Path)
 	b = pbit32(b, d.Mode)
 	b = pbit32(b, d.Atime)
 	b = pbit32(b, d.Mtime)
@@ -101,9 +101,9 @@ func UnmarshalDir(b []byte) (*Dir, error) {
 	var d Dir
 	d.Type, b = gbit16(b)
 	d.Dev, b = gbit32(b)
-	d.Qid.Path, b = gbit64(b)
-	d.Qid.Vers, b = gbit32(b)
 	d.Qid.Type, b = gbit8(b)
+	d.Qid.Vers, b = gbit32(b)
+	d.Qid.Path, b = gbit64(b)
 	d.Mode, b = gbit32(b)
 	d.Atime, b = gbit32(b)
 	d.Mtime, b = gbit32(b)