removed unneeded script

manifest.json

@@ -20,7 +20,6 @@
 				"index.js",
 				"lib/browser-polyfill/chrome-browser-polyfill.js",
 				"lib/hooks/content/content-hooks-frames.js",
-				"lib/single-file/single-file-util.js",
 				"lib/single-file/single-file-helper.js",
 				"lib/frame-tree/content/content-frame-tree.js"
 			],