Otherwise a new client acquiring the connection could be affected by
things happening in channels that were not opened by that client, which
would certainly be unexpected.
In particular, if the new owner of the connection runs in a different
thread than the old one, crashes could occur since the connection
assumes its channels run in the same thread.

Change-Id: I4fdf2b5a3751ed506631d6878e94342da033c31c
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>