Change gae to apache 2 license.

service/datastore/multiarg.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 datastore
 
 import (
         "fmt"
         "reflect"
 
         "github.com/luci/luci-go/common/errors"
 )
 
@@ skipping 525 matching lines @@
         default:
                 // Pass through to track as MultiError.
                 bt.errorTracker.trackError(it, err)
         }
 }
 
 func (bt *boolTracker) result() *ExistsResult {
         bt.res.updateSlices()
         return &bt.res
 }