Fix vmdef usage after domain crash in monitor on device detach
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1161024
    
    In the device type-specific functions, exit early
    if the domain has disappeared, because the cleanup
    should have been done by qemuProcessStop.
    
    Check the return value in processDeviceDeletedEvent
    and qemuProcessUpdateDevices.
    
    Skip audit and removing the device from live def because
    it has already been cleaned up.