simple clients: flush before destroying wl_display

Flush our pending destroy requests to the server before destroying the
wl_display.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>

clients/simple-egl.c

@@ -386,6 +386,7 @@ main(int argc, char **argv)
 	if (display.compositor)
 		wl_compositor_destroy(display.compositor);
 
+	wl_display_flush(display.display);
 	wl_display_destroy(display.display);
 
 	return 0;

clients/simple-shm.c

@@ -235,6 +235,7 @@ destroy_display(struct display *display)
 	if (display->compositor)
 		wl_compositor_destroy(display->compositor);
 
+	wl_display_flush(display->display);
 	wl_display_destroy(display->display);
 	free(display);
 }