Xi: ensure the deviceid for DeviceChangedEvents is always the right one

If we're sending the event for a given device, make sure the deviceid is
that of the device.
This allows callers to use the same DCE for slave and master without having
to fiddle the DCE's internal fields.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Daniel Stone <daniel@fooishbar.org>

Xi/exevents.c

@@ -699,6 +699,7 @@ ChangeMasterDeviceClasses(DeviceIntPtr device, DeviceChangedEvent *dce)
 
     /* FIXME: the classes may have changed since we generated the event. */
     DeepCopyDeviceClasses(slave, device, dce);
+    dce->deviceid = device->id;
     XISendDeviceChangedEvent(device, dce);
 }