Log Message:
Update cyrus-imapd24 to 2.4.3.

Changes to the Cyrus IMAP Server since 2.4.2

      * Many fixes to replication edge case handling
      * Added missing flags to reconstruct
      * Replicate DELETED.user folders in sync_client -u (matches XFER
        behaviour now)
      * Make sync_client only connect after forking in rolling mode. Fixes
        two things - ssl crashes due to shared resource conflicts, and also
        means master will start up even if the replica is not contactable
      * Fixed crash on cyr_expire and ipurge annotation based expiry
      * Many XFER fixes for compatibility across versions:

          * allowing XFER in from delayed_expunge mailboxes
          * allowing XFER back all the way to Cyrus 2.2.12. This was
            accomplished by adding logic that can generate
            backwards-compatible older version indexes, and version
            detection from the imapd banner.
          * correctly fixing seen information for sub-mailboxes on XFER in

      * Multi-target replication. Strictly this is a new feature - there
        was a broken implementation in 2.4.0, which is how this snuck in to
        the bugfix release. It's not super-well documented yet, but it
        works by creating a separate log file for each destination
        "channel", and then running one sync_client process per channel, so
        replication can fall behind on one without affecting replication to
        the other.
      * Fixed some crashes and errors which occured when upgrading and
        opening corrupted mailboxes
      * Modified AFS ptloader configure options to allow building on more
        modern systems