Update _stream_readable.js to delete invalid parameter.

[izengliang]

Update _stream_readable.js to delete invalid parameter.

https://github.com/liangzeng/node/commit/acbb6d5489e31a35b8bc54060b5fabab6edbc6f0

[addaleax]

Hi @liangzeng! You’re right, that change seems to make sense. Do you want to try and open a pull request with it? There is a bit of information on how pull requests should look like in the CONTRIBUTING.md, and feel free to ask anything here if you’re not sure about something.

[izengliang]

@addaleax thanks, i do.