Milo: Fix issues with expiring builds due to builder disappearing

milo/appengine/buildbot/pubsub.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 buildbot
 
 import (
         "bytes"
         "compress/gzip"
         "compress/zlib"
@@ skipping 219 matching lines @@
                 builder, ok := master.Builders[b.Buildername]
                 if !ok {
                         // Mark this build due to builder being removed.
                         logging.Infof(c, "Expiring %s/%s/%d due to builder being removed",
                                 master.Name, b.Buildername, b.Number)
                         err = expireBuild(c, b)
                         if err != nil {
                                 logging.WithError(err).Errorf(c, "Could not expire build")
                                 return 500
                         }
+                        continue

[hinoka, 2016/10/27 01:31:22]

Continue because we're done with this build

                 }
 
                 found := false
                 for _, bnum := range builder.CurrentBuilds {

[hinoka, 2016/10/27 01:31:22]

builder is nil here otherwise.

                         if b.Number == bnum {
                                 found = true
                                 break
                         }
                 }
                 if !found {
                         // Mark this build due to build not current anymore.
                         logging.Infof(c, "Expiring %s/%s/%d due to build not current",
                                 master.Name, b.Buildername, b.Number)
                         err = expireBuild(c, b)
@@ skipping 115 matching lines @@
         }
         if master != nil {
                 code := doMaster(c, master, internal)
                 if code != 0 {
                         h.WriteHeader(code)
                         return
                 }
         }
         h.WriteHeader(200)
 }