[Dovecot] real_rip variable addition for dovecot 2.1.10

[Jack Bates]

Timo,

Please check the code. I didn't add it, but a real_lip might be useful 
for some people as well. Also, I notice that pop3-proxy is doing a 
different xsession than the imap proxy. Is there an xsession standard 
that is different between the two, or just an oversight in the code? 
Both send the remote address/port, but only imap proxy sends the local 
address/port.

This patch declares long variable %{real_rip} so that a backend server 
can declare a different login_log_format_elements
login_log_format_elements = user=<%u> method=%m rip=%r lip=%l 
pip=%{real_rip} mpid=%e %c

This is primarily useful for backend servers to log both the rip, lip, 
and in case of xsession, the real rip. I haven't done extensive testing 
yet, but as long as nothing does anything weird elsewhere in the code, 
it should be good.

http://www.brightok.net/jbates/dovecot-2.1.10-real-ip.patch

dovecot: pop3-login: Login: user=<test>, method=PLAIN, rip=192.168.1.5, 
lip=::1, pip=::1, mpid=8665, secured


Jack Bates