style-collector.js doesn't collect any styles

[goldensunliu]

I noticed that https://github.com/webpack/react-webpack-server-side-example/blob/master/server/style-collector.js#L4 was never called during an execution of its collect method. I think it may have to do with the fact that webpack caches the style-collector.js on first require: https://github.com/webpack/webpack/blob/76230e4a4e4389e622c04ead1d79a7a7e122bd21/lib/MainTemplate.js#L48.

on this line https://github.com/webpack/react-webpack-server-side-example/blob/master/server/style-collector.loader.js#L5, was the intention to delete the module cache for style-collector.js. It currently removes the css style modules. I am a bit confused on what it is trying to do here.

[gf3]

cc: @sokra