GAE CL for luci-go common refactor

impl/memory/datastore_index_selection.go

 // 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 memory
 
 import (
         "bytes"
         "fmt"
         "sort"
         "strings"
 
         ds "github.com/luci/gae/service/datastore"
         "github.com/luci/gae/service/datastore/serialize"
-        "github.com/luci/luci-go/common/stringset"
+        "github.com/luci/luci-go/common/data/stringset"
 )
 
 // ErrMissingIndex is returned when the current indexes are not sufficient
 // for the current query.
 type ErrMissingIndex struct {
         ns      string
         Missing *ds.IndexDefinition
 }
 
 func (e *ErrMissingIndex) Error() string {
@@ skipping 516 matching lines @@
                 if bestIdx == nil {
                         // something is really wrong here... if relevantIdxs is !nil, then we
                         // should always be able to make progress in this loop.
                         impossible(fmt.Errorf("deadlock: cannot fulfil query?"))
                 }
                 ret = append(ret, generate(q, bestIdx, constraints))
         }
 
         return ret, nil
 }