[JDEV] jabberd patch

[Wes Morgan]

I forgot to mention why I needed this behavior in the first place... I 
implemented a custom web-based chat system for a client that uses jabberd as 
its backend. However, one of the requirements for the system was that users 
could only log on once, and that if they tried to log on a second time, they 
wouldn't be allowed (unless, of course, they terminated the first session). I 
had been keeping track of this in a state database that my auth agent was 
using (it communicates with jabberd at the XDB level), but sometimes jabberd 
and this database would get out of sync with each other. So, I decided to 
just build this functionality into jabberd itself. That's why, for my needs, 
it wouldn't work to just "define the protocol" as kicking the first 
connection when a second one comes along. I at least need the option of 
changing the functionality.

Wes Morgan