Code review comment for lp:~paulliu/unity-mir/logout

Results from the discussion with Saviq and mzanetti in #ubuntu-unity:

- This is a "quick & dirty" interim implementation to get things going as currently there's not grand plan or architecture for the logout story. This story need more thought.
- We don't want to pollute or complicate AppMan API with "quick & dirty" changes.

Thus:
Leave ApplicationManager as it is. You can achieve the same result with the existing API. Just move the loop to close all apps to unity8. And move DBusUnitySessionService along with it. Check unity8/plugins sub dir (LightDm and Utils also register dbus services).