-tls-on-connect support

[Antti S. Lankila]

I submit the following patch for your consideration:

http://bel.fi/~alankila/exim4.diff

This is a diff against /etc/init.d/exim version 4.67-5. It adds the 
necessary support for these two lines in /etc/default/exim4 that I 
cooked up:

# options to get a listener at 465
STARTBROKENSSL=1
SSLSMTPLISTENEROPTIONS='-tls-on-connect -oX 0.0.0.0:465'

As of today, there are still email applications which think TLS support 
means contacting the mailer at port 465 and speaking TLS directly (such 
as Nokia 9500 phone). If the START line is commented out, the changes to 
/etc/init.d/exim should do nothing at all. If it isn't commented out, it 
starts a new process labelled exim4_listener_ssl. (I use the name 'SSL' 
to separate it from 'TLS' at this point, similar to how these terms are 
used in Thunderbird.)

I have only tested the 'combined' and 'separate' queuerunner modes so 
far. Both seem to work.

-- 
Antti Lankila <alankila at bel.fi>