[milo] {buildbucket,buildbot,swarming,logdog} -> backends/*.

milo/appengine/backends/buildbucket/builder_test.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 buildbucket
 
 import (
         "encoding/json"
         "flag"
         "fmt"
@@ skipping 64 matching lines @@
 buildbucket: {
         host: "debug"
 }
 `
 
 var bktConfigFull = map[string]memcfg.ConfigSet{
         "services/luci-milo-dev": {
                 "settings.cfg": bktConfig,
         },
 }