Fix deprecation warning in for using EmberApp.concatFiles

Author: Gaurav0

lib/ext/patch-ember-app.js

@@ -21,7 +21,7 @@ function patchEmberApp(emberApp) {
     if (options.annotation === 'Concat: App') {
       tree = this.addonPreconcatTree(tree);
     }
-    return originalConcatFiles.call(this, tree, options);
+    return originalConcatFiles.apply(this, arguments);
   };
 }