go.net: use golang.org/x/... import paths

de/08.2.md

@@ -107,7 +107,7 @@ Server code:
 	package main
 
 	import (
-		"code.google.com/p/go.net/websocket"
+		"golang.org/x/net/websocket"
 		"fmt"
 		"log"
 		"net/http"

ja/08.2.md

@@ -99,7 +99,7 @@ WebSocketはクライアントとサーバに分けられます。ここでは
 	package main
 
 	import (
-		"code.google.com/p/go.net/websocket"
+		"golang.org/x/net/websocket"
 		"fmt"
 		"log"
 		"net/http"

pt-br/08.2.md

@@ -107,7 +107,7 @@ Server code:
 	package main
 
 	import (
-		"code.google.com/p/go.net/websocket"
+		"golang.org/x/net/websocket"
 		"fmt"
 		"log"
 		"net/http"

zh/08.2.md

@@ -99,7 +99,7 @@ WebSocket分为客户端和服务端，接下来我们将实现一个简单的
 	package main
 
 	import (
-		"code.google.com/p/go.net/websocket"
+		"golang.org/x/net/websocket"
 		"fmt"
 		"log"
 		"net/http"