compositor: do not free output region twice in weston_output_set_transform()

This is already done when weston_output_init_geometry() is called.
Actually this is a fix for 8564a0d, because without this patch, the
compositor sometimes crashes when setting output transform

Signed-off-by: Ilia Bozhinov <ammen99@gmail.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

libweston/compositor.c

@@ -4706,9 +4706,6 @@ weston_output_set_transform(struct weston_output *output,
 	pixman_region32_init(&old_region);
 	pixman_region32_copy(&old_region, &output->region);
 
-	pixman_region32_fini(&output->region);
-	pixman_region32_fini(&output->previous_damage);
-
 	weston_output_init_geometry(output, output->x, output->y);
 
 	output->dirty = 1;