Change gae to apache 2 license.

service/logging/logging.go

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
+// Copyright 2015 The LUCI Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
 
 // Package logging is simply documentation :)
 //
 // In order to use logging, please import and use the
 // "github.com/luci/luci-go/common/logging" package. Both
 // "github.com/luci/gae/impl/prod" and "github.com/luci/gae/impl/memory"
 // implement that service appropriately.
 package logging