sna: Unregister the BlockHandler on close

Now that we register a callback with an external stack and not the
screen, we have to remove it when the screen is destroyed.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

src/sna/sna_driver.c

@@ -949,6 +949,12 @@ static Bool sna_early_close_screen(CLOSE_SCREEN_ARGS_DECL)
 
 	/* XXX Note that we will leak kernel resources if !vtSema */
 
+#if HAVE_NOTIFY_FD
+	RemoveBlockAndWakeupHandlers(sna_block_handler,
+				     (ServerWakeupHandlerProcPtr)NoopDDA,
+				     sna);
+#endif
+
 	sna_uevent_fini(sna);
 	sna_mode_close(sna);