Milo: Use custom config caching layer

milo/appengine/common/acl.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 common
 
 import (
         "golang.org/x/net/context"
 
         "github.com/luci/luci-go/luci_config/common/cfgtypes"
@@ skipping 17 matching lines @@
         case access.ErrNoAccess:
                 return false, nil
         default:
                 return false, err
         }
 }
 
 // IsAllowedInternal is a shorthand for checking to see if the user is a reader
 // of a magic project named "chrome".
 func IsAllowedInternal(c context.Context) (bool, error) {
-        settings, err := GetSettings(c)
-        if err != nil {
-                return false, err
+        settings := GetSettings(c)
+        if settings.Buildbot.InternalReader == "" {
+                return false, nil
         }
         return auth.IsMember(c, settings.Buildbot.InternalReader)
 }