Code review comment for lp://qastaging/~mterry/lightdm/shut-down-dbus

Ech. LightDM really doesn't know (or care) what the greeter is so doing this is making big assumptions about the greeter behaviour. All processes spawned by the greeter should be killed, but this is probably better solved using cgroups.

We should move this into the gtk-greeter / Unity greeter, as hacks are OK there, but I'd like to keep this sort of thing out of lightdm core.