fs: fix hasOwnProperty issue for readStream/writeStream options

The hasOwnProperty that pass in make the createReadStream failed.
```
var reader = fs.createReadStream(__filename, {
  hasOwnProperty: function () {
    return true;
  }
});
```
Result: 
```
fs.js:434
  binding.open(pathModule._makeLong(path),
          ^
TypeError: flags must be an int
    at TypeError (native)
    at Object.fs.open (fs.js:434:11)
    at ReadStream.open (fs.js:1503:6)
    at new ReadStream (fs.js:1490:10)
    at Object.fs.createReadStream (fs.js:1444:10)
    at Object.<anonymous> (/Users/jacksontian/git/node_research/stream/readable.js:3:17)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:349:32)
    at Function.Module._load (module.js:305:12)
```
Nvm... let me think about it