backends: don't destroy renderer and output twice

drm, fbdev, rpi and wayland backends are unnecessarily destroying
renderer and output before executing weston_compositor_shutdown()

Signed-off-by: Dawid Gajownik <gajownik@gmail.com>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>
diff --git a/src/compositor-fbdev.c b/src/compositor-fbdev.c
index 3110f74..051a381 100644
--- a/src/compositor-fbdev.c
+++ b/src/compositor-fbdev.c
@@ -881,16 +881,13 @@
 	}
 
 	if (fbdev_output_create(backend, param->device) < 0)
-		goto out_pixman;
+		goto out_launcher;
 
 	udev_input_init(&backend->input, compositor, backend->udev, seat_id);
 
 	compositor->backend = &backend->base;
 	return backend;
 
-out_pixman:
-	compositor->renderer->destroy(compositor);
-
 out_launcher:
 	weston_launcher_destroy(compositor->launcher);