senddigests crashes when a whole message is discarded

[Hatukanezumi-users]

Traceback (most recent call last):
  File "/usr/local/mailman/cron/senddigests", line 94, in ?
    main()
  File "/usr/local/mailman/cron/senddigests", line 86,
in main
    mlist.send_digest_now()
  File "/usr/local/mailman/Mailman/Digester.py", line
60, in send_digest_now
    ToDigest.send_digests(self, mboxfp)
  File
"/usr/local/mailman/Mailman/Handlers/ToDigest.py", line
130, in send_digests
    send_i18n_digests(mlist, mboxfp)
  File
"/usr/local/mailman/Mailman/Handlers/ToDigest.py", line
303, in send_i18n_digests
    msg = scrubber(mlist, msg)
  File
"/usr/local/mailman/Mailman/Handlers/Scrubber.py", line
179, in process
    raise DiscardMessage
Mailman.Errors.DiscardMessage

[http://sourceforge.net/tracker/index.php?func=detail&aid=780051&group_id=103&atid=100103]

[Hatukanezumi-users (hatukanezumi-users)]

this is duplicate to patch #860135.