[logdog] Replace Tumble with push queues.

logdog/appengine/cmd/coordinator/backend/module-backend.yaml

 # Copyright 2017 The LUCI Authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
 service: backend
 runtime: go
 api_version: go1
 
-instance_class: IC_2
+instance_class: F2
 
 handlers:
 - url: "/debug/*"
   script: _go_app
   secure: always
   login: admin
 
+- url: "/internal/*"
+  script: _go_app
+  secure: always
+  login: admin
+
 - url: "/.*"
   script: _go_app
   secure: always
   login: admin