go.tools/cmd/godoc: register redirect handler for /dl/

LGTM=minux
R=golang-codereviews, gobot, bradfitz, minux
CC=golang-codereviews
https://golang.org/cl/107050044

cmd/godoc/dl.go

@@ -0,0 +1,14 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "net/http"
+
+// Register a redirect handler for /dl/ to the golang.org download page.
+// This file will not be included when deploying godoc to golang.org.
+
+func init() {
+	http.Handle("/dl/", http.RedirectHandler("http://golang.org/dl/", http.StatusFound))
+}