[Dovecot] Do not keep persistent logs in a container

data/Dockerfiles/dovecot/supervisord.conf

@@ -3,19 +3,16 @@ nodaemon=true
 
 [program:syslog-ng]
 command=/usr/sbin/syslog-ng --foreground --no-caps
-redirect_stderr=true
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
 autostart=true
-stdout_syslog=true
 
 [program:dovecot]
 command=/usr/local/sbin/dovecot -F
 autorestart=true
 
-[program:logfiles]
-command=/usr/bin/tail -f /var/log/combined.log
-stdout_logfile=/dev/fd/1
-stdout_logfile_maxbytes=0
-
 [program:cron]
 command=/usr/sbin/cron -f
 autorestart=true