[Dovecot] v2.2.4 released

[Timo Sirainen]

http://dovecot.org/releases/2.2/dovecot-2.2.4.tar.gz
http://dovecot.org/releases/2.2/dovecot-2.2.4.tar.gz.sig

OK, this should be a pretty good and stable version.

        + doveadm: Added "flags" command to modify message flags.
        + doveadm: Added "deduplicate" command to expunge message duplicates.
        + dsync: Show the state in process title with verbose_proctitle=yes.
        - imap/pop3 proxy: Master user logins were broken in v2.2.3
        - sdbox/mdbox: A corrupted index header with wrong size was never
          automatically fixed in v2.2.3.
        - mbox: Fixed assert-crashes related to locking.