fix runtime directive unbind

src/runtime/vdom/modules/directives.js

@@ -5,8 +5,8 @@ export default {
   update: function (oldVnode, vnode) {
     applyDirectives(oldVnode, vnode, 'update', true)
   },
-  destroy: function (oldVnode, vnode) {
-    applyDirectives(oldVnode, vnode, 'unbind')
+  destroy: function (vnode) {
+    applyDirectives(null, vnode, 'unbind')
   }
 }