v2.2.33 release candidate released

[Timo Sirainen]

https://dovecot.org/releases/2.2/rc/dovecot-2.2.33.rc1.tar.gz
https://dovecot.org/releases/2.2/rc/dovecot-2.2.33.rc1.tar.gz.sig 

There are a couple more small changes still coming, but this should be very close to the final release. I'm especially interested in hearing if there are any problems with doveadm log proxying or with director. We've improved our automated director tests quite a lot now, and fixed some rarely occurring bugs.

 * doveadm director commands wait for the changes to be visible in the
   whole ring before they return. This is especially useful in testing.
 * Environments listed in import_environment setting are now set or
   preserved when executing standalone commands (e.g. doveadm)

 + doveadm proxy: Support proxying logs. Previously the logs were
   visible only in the backend's logs.
 + Added %{if}, see https://wiki2.dovecot.org/Variables#Conditionals
 + Added a new notify_status plugin, which can be used to update dict
   with current status of a mailbox when it changes. See
   https://wiki2.dovecot.org/Plugins/NotifyStatus
 + Mailbox list index can be disabled for a namespace by appending
   ":LISTINDEX=" to location setting.
 + dsync/imapc: Added dsync_hashed_headers setting to specify which
   headers are used to match emails.
 + pop3-migration: Add pop3_migration_ignore_extra_uidls=yes to ignore
   mails that are visible in POP3 but not IMAP. This could happen if
   new mails were delivered during the migration run.
 + pop3-migration: Further improvements to help with Zimbra
 + pop3-migration: Cache POP3 UIDLs in imapc's dovecot.index.cache
   if indexes are enabled. These are used to optimize incremental syncs.
 + cassandra, dict-sql: Use prepared statements if protocol version>3.
 - sdbox: Mails were always opened when expunging, unless
   mail_attachment_fs was explicitly set to empty.
 - lmtp/doveadm proxy: hostip passdb field was ignored, which caused
   unnecessary DNS lookups if host field wasn't an IP
 - lmtp proxy: Fix crash when receiving unexpected reply in RCPT TO
 - quota_clone: Update also when quota is unlimited (broken in v2.2.31)
 - mbox, zlib: Fix assert-crash when accessing compressed mbox
 - doveadm director kick -f parameter didn't work
 - doveadm director flush <host> resulted flushing all hosts, if <host>
   wasn't an IP address.
 - director: Various fixes to handling backend/director changes at
   abnormal times, especially while ring was unsynced. These could have
   resulted in crashes, non-optimal behavior or ignoring some of the
   changes.
 - director: Use less CPU in imap-login processes when moving/kicking
   many users.
 - lmtp: Session IDs were duplicated/confusing with multiple RCPT TOs
   when lmtp_rcpt_check_quota=yes
 - doveadm sync -1 fails when local mailboxes exist that do not exist
   remotely. This commonly happened when lazy_expunge mailbox was
   autocreated when incremental sync expunged mails.