recipe build for removed recipe triggers uploader exception

When a recipe build has been removed since a recipe build was started the archive uploader will fall over:

OOPS-1832FTPMASTER446

Traceback (most recent call last):
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/services/scripts/base.py", line 91, in log_unhandled_exceptions_func
    return func(self, *args, **kw)
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/services/scripts/base.py", line 353, in lock_and_run
    implicit_begin=implicit_begin, isolation=isolation)
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/services/scripts/base.py", line 91, in log_unhandled_exceptions_func
    return func(self, *args, **kw)
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/services/scripts/base.py", line 311, in run
    self.main()
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/soyuz/scripts/soyuz_process_upload.py", line 93, in main
    processor.processUploadQueue(self.options.leafname)
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/archiveuploader/uploadprocessor.py", line 196, in processUploadQueue
    self.processBuildUpload(fsroot, upload)
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/archiveuploader/uploadprocessor.py", line 257, in processBuildUpload
    build.notify(extra_info="Uploading build %s failed." % upload)
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/code/model/sourcepackagerecipebuild.py", line 280, in notify
    mailer.sendAll()
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/services/mail/basemailer.py", line 151, in sendAll
    ctrl = self.generateEmail(email, recipient)
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/services/mail/basemailer.py", line 76, in generateEmail
    subject = self._getSubject(email)
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/services/mail/basemailer.py", line 91, in _getSubject
    return self._subject_template % self._getTemplateParams(email)
  File "/srv/launchpad.net/codelines/soyuz-production-rev-12161/lib/lp/code/mail/sourcepackagerecipebuild.py", line 60, in _getTemplateParams
    'recipe': self.build.recipe.name,
AttributeError: 'NoneType' object has no attribute 'name'

It should explicitly check if the recipe still exists, and otherwise discard the build.