Code review comment for lp:~jamesodhunt/upstart/bugs-1235649+1203595

I was assuming you would replace this with a fresh branch, based on our discussion, since it will have almost nothing in common with the current code. :) So rejecting this mp.

As we discussed, a better approach is to make this explicit rather than implicit by having a new initctl interface that takes the dbus address as an argument. When a session init receives this call, it should connect to the dbus session bus at the specified address if it isn't already connected to the session bus. (Requests to connect to a session bus if there's already a session bus should be ignored.) This way, we don't have to fiddle with the environment at all.