add comment to generated file

jio_fs2erp5storage.js

@@ -529,6 +529,7 @@
             }
           },
           text_content: "CACHE MANIFEST\nCACHE:\n" +
+          "#autogenerated for: " + context._options.name +
           generated_appcache.join("\n") + "\nNETWORK:\n*"
         };
         context._id_dict[context.path_prefix_file + "web_page_module/"]