v2.2.23 released

[Timo Sirainen]

http://dovecot.org/releases/2.2/dovecot-2.2.23.tar.gz
http://dovecot.org/releases/2.2/dovecot-2.2.23.tar.gz.sig

This is a bugfix-only release with various important fixes on top of v2.2.22.

 - Various fixes to doveadm. Especially running commands via
   doveadm-server was broken.
 - director: Fixed user weakness getting stuck in some situations
 - director: Fixed a situation where directors keep re-sending
   different states to each others and never becoming synced.
 - director: Fixed assert-crash related to a slow "user killed" reply
 - Fixed assert-crash related to istream-concat, which could have
   been triggered at least by a Sieve script.