fs: fix fd leak in ReadStream.destroy()

PR-URL: https://github.com/iojs/io.js/pull/56
Reviewed-By: Rod Vagg <rod@vagg.org>

See PR for long discussion

lib/fs.js

@@ -1668,9 +1668,7 @@ ReadStream.prototype.destroy = function() {
   if (this.destroyed)
     return;
   this.destroyed = true;
-
-  if (util.isNumber(this.fd))
-    this.close();
+  this.close();
 };