This is a tracker bug for processes that don't (but should) exit when
a GNOME session is ended.
owen says gam_server is allowed 30 seconds to exit.
I confirm, once all clients have disconnected the gam_server process
exits within 30 seconds.
Assuming that my workaround for bug #134851 is acceptable, it looks
like we can close this tracker
Resolving this one as CURRENTRELEASE, as per comment #3 above.