Fix regression preventing new install or reseting to factory default

Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/431

src/js/storage.js

@@ -256,7 +256,7 @@
             bin instanceof Object === false ||
             Array.isArray(bin.selectedFilterLists) === false
         ) {
-            this.assets.metadata(function(availableLists) {
+            this.assets.metadata(availableLists => {
                 this.saveSelectedFilterLists(
                     this.autoSelectRegionalFilterLists(availableLists)
                 );