Update cloud package.

impl/cloud/datastore.go

 // Copyright 2016 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 cloud
 
 import (
         "fmt"
         "reflect"
         "strings"
         "time"
 
         "github.com/luci/luci-go/common/errors"
 
+        "cloud.google.com/go/datastore"
         ds "github.com/luci/gae/service/datastore"
         infoS "github.com/luci/gae/service/info"
-        "google.golang.org/cloud/datastore"
 
         "golang.org/x/net/context"
 )
 
 type cloudDatastore struct {
         client *datastore.Client
 }
 
 func (cds *cloudDatastore) use(c context.Context) context.Context {
         return ds.SetRawFactory(c, func(ic context.Context, wantTxn bool) ds.RawInterface {
@@ skipping 495 matching lines @@
         case datastore.ErrNoSuchEntity:
                 return ds.ErrNoSuchEntity
         case datastore.ErrConcurrentTransaction:
                 return ds.ErrConcurrentTransaction
         case datastore.ErrInvalidKey:
                 return ds.ErrInvalidKey
         default:
                 return err
         }
 }