doveconf non-syntax check

[dovecot at ptld.com]

> root at unix:/etc/dovecot# dovecot -F
> doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf
> 
> ...maybe it's useful to add a 'quiet' option (i.e. no stdout) to 
> doveconf.


dovecot -F  > /dev/null 2>&1

:)