dix: don't attempt to deliver an event for a different grabtype

For an active grab, grab->eventMask can be either the core or the XI1 mask.
With the overlap of event filters, calling DeliverOneGrabbedEvent(XI1) for a
ProximityOut event will trigger if the client has selected for enter events -
the filter is the same for both.

Thus, we end up delivering a proximity event to a client not expecting one.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit 78944d62ff)

dix/events.c

@@ -4139,6 +4139,9 @@ DeliverOneGrabbedEvent(InternalEvent *event, DeviceIntPtr dev,
     GrabPtr grab = grabinfo->grab;
     Mask filter;
 
+    if (grab->grabtype != level)
+        return 0;
+
     switch (level) {
     case XI2:
         rc = EventToXI2(event, &xE);