SIGSEGV bugs wsubus.impl.h when an origin access check fails

I fixed a couple of SIGSEGV bugs wsubus.impl.h when an origin access check fails (see below).

static inline void wsu_peer_deinit(struct lws *wsi, struct wsu_peer *peer)
{
	if (peer->curr_msg.jtok) {
		json_tokener_free(peer->curr_msg.jtok);
		peer->curr_msg.jtok = NULL;
	}

	if (peer->write_q.next) {

		// free everything from write queue
		struct wsu_writereq *p, *n;
		list_for_each_entry_safe(p, n, &peer->write_q, wq) {
			lwsl_info("free write in progress %p\n", p);
			list_del(&p->wq);
			free(p);
		}
	}

	if (peer->role == WSUBUS_ROLE_CLIENT) {
		struct prog_context *prog = lws_context_user(lws_get_context(wsi));

		// cancel each access check in progress
		//
		// NOTE:
		// it is important that first we cancel access checks in progress
		// (before cancelling calls in progress), since access check may
		// reference a pending call in progress (namely a call to ubus session
		// object)
		if (peer->u.client.access_check_q.next) {
			struct wsubus_client_access_check_ctx *p, *n;
			list_for_each_entry_safe(p, n, &peer->u.client.access_check_q, acq) {
				lwsl_info("free check in progress %p\n", p);
				list_del(&p->acq);
				wsubus_access_check__cancel(prog->ubus_ctx, p->req);
				wsubus_access_check_free(p->req);
				if (p->destructor)
					p->destructor(p);
			}
		}

		if (peer->u.client.rpc_call_q.next) {
			struct list_head *p, *n;
			// cancel all calls in progress
			list_for_each_safe(p, n, &peer->u.client.rpc_call_q) {
				list_del(p);
				struct ws_request_base *base = container_of(p, struct ws_request_base, cq);
				if (base->cancel_and_destroy) {
					lwsl_debug("free req in progress %p\n", base);
					base->cancel_and_destroy(base);
				}
			}
		}
	}
}