Path module in webpack config is not used after eject

[harunhasdal]

Nodejs path module is not used in webpack.config.dev.js and webpack.config.prod.js after ejecting.

This results in ESLint warning for no-unused-var rule.

[gaearon]

Would you like to fix it? You can wrap its import in // @remove-on-eject-begin and // @remove-on-eject-end.

[harunhasdal]

Sure, creating a PR now.