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

milo/appengine/backends/buildbucket/common.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 (
         "fmt"
         "net/http"
         "strings"
@@ skipping 131 matching lines @@
                 }
         }
 
         if result != nil && len(params.Changes) != 0 {
                 // tryjobs have one change and it is the CL author
                 result.AuthorEmail = params.Changes[0].Author.Email
         }
 
         return
 }