[patch] do not segfault when D-Bus connection is reused

[Havoc Pennington]

John (J5) Palmieri wrote:
> So, if we assume the owner of shared connections is the library and
> everything else is the user what do we do if you try to close the shared
> connection?  We can't send back errors since that would be an API
> change.  Do we warn or do we just go on our merry way?
> 

If we can detect it I think warning would be good. It's basically a 
programming error.

To warn I think we'd need a "shared" flag in the connection object or 
something, and then we have a special internal close method we use in 
the library that does not warn if this flag is set.

Havoc