Comment 71 for bug 1235649

After discussing this with Ted, I think the right answer architecturally is to move these clients to talking to the session bus, where filtering of messages will be done for us automatically, and have the session init register on the session bus, rather than deploying an unreliable change like having upstart only keep one message at a time in the queue for a client. This will require a few changes in upstart, including working out the correct way to get the session init to register with the session bus after dbus has been spawned (presumably we want to reuse SIGUSR1 for this, and maybe get the session bus address out of the global environment?)