If we want to support multiple backends, the compositor must take care
to call this once, at the appropriate moment, so stop letting the
backends handle compositor shutdown themselves.
Move the weston_compositor_shutdown() calls from the backend::destroy
callbacks into weston_compositor_destroy() and the calls in the backend
creation error paths into weston_compositor_load_backend().
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
90c11cf40e