remove importLoaders from css modules default options (#932)

* remove DEFAULT_OPTIONS

* revert back DEFAULT_OPTIONS for modules option

Author: vanhoavn

lib/loader.js

@@ -481,11 +481,11 @@ module.exports = function (content) {
     if (!part.module) return loader
     const option = options.cssModules || {}
     const DEFAULT_OPTIONS = {
-      modules: true,
-      importLoaders: true
+      modules: true
     }
     const OPTIONS = {
-      localIdentName: '[hash:base64]'
+      localIdentName: '[hash:base64]',
+      importLoaders: true
     }
     return loader.replace(/((?:^|!)css(?:-loader)?)(\?[^!]*)?/, (m, $1, $2) => {
       // $1: !css-loader