Log Message:
Update cyrus-imapd24 to 2.4.20

Changes in 2.4.19:

  * Complete backport of the new (2.5 and later) IMAP IDLE implementation
    (thanks Thomas Jarosh). This fixes a bunch of bugs and race conditions
    that were inherent to the older implementation
  * New option "imapidletimeout" overrides "timeout" \ 
specifically for
    connections in IDLE state
  * OpenSSL 1.1.0 is now supported
  * Fixed: imap ENABLED doesn't print * ENABLED when nothing new enabled
  * Fixed: mailbox lock management over rename (thanks Thomas Jarosh)
  * Fixed: added overflow protection to urlfetch range checks
  * Fixed: lmtpd can now deliver when mupdate server isn't available
    (thanks Michael Menge)
  * Fixed task 227: service processes no longer divide by zero when
    invoked with -T 0 argument (thanks Ian Batten and Jens Erat)
  * Fixed task 229: ctl_cyrusdb now uses database paths from imapd.conf
    (thanks Simon Matter)
  * Fixed bug #3862: mailbox database changes now rolled back on mupdate
    failure during rename (thanks Michael Menge)
  * Fixed: XFER to 2.5 and later no longer downgrades index to oldest version
  * Fixed: nonsensical "TEXT.MIME" section now handled as \ 
"HEADER"
  * Fixed: added missing 'auditlog: ' prefix to backend connections
    (thanks Wolfgang Breyha)
  * Fixed: IMAP SEARCH crash on some platforms
  * Fixed: memory leaks in IMAP SEARCH and IMAP APPEND
  * Fixed Issue #1967: EXISTS count reported earlier if fetching past size
    of previous message set

Changes in 2.4.20:

  * Fixed: lmtpd crash
  * Fixed: auth_pts will now error if its configured socket path is too
    long for its buffer