Add missing Statslog() statements (loglevel stats/stats2):

  "ABANDON", "STARTTLS", "CANCEL", "WHOAMI", "PASSMOD", "EXT", "INTERM",
  "TLS established", SASL and Extended Response "RESULT".
In Statslog output "conn=xx fd=yy closed", append the reason in
  "()" unless client or server closed the connection after Unbind.
Still missing Statslog output from a number of failed requests.