Make relative ref to sys in fs module.

lib/fs.js

@@ -1,7 +1,5 @@
-var
-  sys = require('sys'),
-  events = require('events'),
-  fs = require('fs');
+var sys = require('./sys'),
+    events = require('events');
 
 exports.Stats = process.Stats;
 
@@ -660,4 +658,4 @@ var FileWriteStream = exports.FileWriteStream = function(path, options) {
 
   flush();
 };
-sys.inherits(FileWriteStream, events.EventEmitter);
+sys.inherits(FileWriteStream, events.EventEmitter);