gtk/main: Do not use touchpad event sequence for pointer focus lookup

Despite touchpad gestures having a sequence, these must use the logical
pointer focus. Avoid using the sequence for GtkPointerFocus lookups with
those events, in order to ensure those events make it all the way to the
intended target.

This is fallout from adding GdkEventSequence information to touchpad
gestures.

gtk/gtkmain.c

@@ -1352,6 +1352,14 @@ handle_pointing_event (GdkEvent *event)
        */
       device = gdk_seat_get_pointer (gdk_event_get_seat (event));
     }
+  else if (type == GDK_TOUCHPAD_PINCH ||
+           type == GDK_TOUCHPAD_SWIPE)
+    {
+      /* Another bit of a kludge, touchpad gesture sequences do not
+       * reflect on the pointer focus lookup.
+       */
+      sequence = NULL;
+    }
 
   switch ((guint) type)
     {