Devices are only activated once - right after they've been added to the
server. If a device failes activation, it's dead. There's no reason to
continue. Return the error code from ActivateDevice() without setting up
sprite information or even sending a event to the client.
Then - in the DDX - just remove the device again.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>