fix my carelessness in e19e879
fix my carelessness in e19e879

- ensure `lib/mocha.js` is linted but `mocha.js` is not

adamgruber/mocha,outsideris/mocha,mochajs/mocha,boneskull/mocha,adamgruber/mocha,boneskull/mocha,mochajs/mocha,outsideris/mocha,igwejk/mocha,adamgruber/mocha,igwejk/mocha,boneskull/mocha,mochajs/mocha