indexeddb: fix iOS behaviour

src/jio.storage/indexeddbstorage.js

@@ -30,6 +30,9 @@
 /*jslint nomen: true */
 /*global indexedDB, jIO, RSVP, Blob, Math, IDBKeyRange*/
 
+var indexedDB = window.indexedDB || window.webkitIndexedDB || window.msIndexedDB
+                || window.mozIndexedDB || window.moz_indexedDB;
+
 (function (indexedDB, jIO, RSVP, Blob, Math, IDBKeyRange) {
   "use strict";