backend-wayland: Avoid iterating over un-intialized lists

As an in-flight resize call might cause a call to
wayland_output_destroy_shm_buffers() to go over a list of free_buffers
list. Just initialize the lists before attempting to create the parent
surface to avoid it.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>

libweston/backend-wayland/wayland.c

@@ -1239,6 +1239,9 @@ wayland_output_enable(struct weston_output *base)
 	enum mode_status mode_status;
 	int ret = 0;
 
+	wl_list_init(&output->shm.buffers);
+	wl_list_init(&output->shm.free_buffers);
+
 	weston_log("Creating %dx%d wayland output at (%d, %d)\n",
 		   output->base.current_mode->width,
 		   output->base.current_mode->height,
@@ -1250,9 +1253,6 @@ wayland_output_enable(struct weston_output *base)
 	if (ret < 0)
 		return -1;
 
-	wl_list_init(&output->shm.buffers);
-	wl_list_init(&output->shm.free_buffers);
-
 	if (b->use_pixman) {
 		if (wayland_output_init_pixman_renderer(output) < 0)
 			goto err_output;