worker: avoid uninitialized pointers

The cookie module could segfault due to the `opt` pointer not being
initialized when no EDNS was sent in the incoming request.

daemon/worker.c

@@ -259,6 +259,8 @@ static struct qr_task *qr_task_create(struct worker_ctx *worker, uv_handle_t *ha
 	task->req.qsource.key = NULL;
 	task->req.qsource.addr = NULL;
 	task->req.qsource.dst_addr = NULL;
+	task->req.qsource.packet = NULL;
+	task->req.qsource.opt = NULL;
 	/* Remember query source addr */
 	if (addr) {
 		size_t addr_len = sizeof(struct sockaddr_in);