Log Message:
Update to 20181124. Changes:

- fixsmtpio: Fix "out of memory" errors with big attachments by handling
  DATA specially (no parsing or copying).
- FIXSMTPIODEBUG: log our pid and child's basename and pid.
- fixsmtpio: Ensure STARTTLS resets all state by restarting qmail-smtpd.

When upgrading, be sure to add this entry to control/fixsmtpio:

    # Remove greeting for child process restarted after upgrading to STARTTLS
    SSL_CIPHER:greeting::2*::