fix: add check for req object on getCookie (#132)

Author: SkyLeite

lib/core/storage.js

@@ -183,7 +183,7 @@ export default class Storage {
   }
 
   getCookie (key, isJson) {
-    if (!this.options.cookie) {
+    if (!this.options.cookie || !this.ctx.req) {
       return
     }