revert back DEFAULT_OPTIONS for modules option

Author: vanhoavn

lib/loader.js

@@ -427,16 +427,18 @@ module.exports = function (content) {
   function addCssModulesToLoader (loader, part, index) {
     if (!part.module) return loader
     var option = options.cssModules || {}
+    var DEFAULT_OPTIONS = {
+      modules: true
+    }
     var OPTIONS = {
       localIdentName: '[hash:base64]',
-      modules: true,
       importLoaders: true
     }
     return loader.replace(/((?:^|!)css(?:-loader)?)(\?[^!]*)?/, function (m, $1, $2) {
       // $1: !css-loader
       // $2: ?a=b
       var query = loaderUtils.parseQuery($2 || '?')
-      Object.assign(query, OPTIONS, option)
+      Object.assign(query, OPTIONS, option, DEFAULT_OPTIONS)
       if (index !== -1) {
         // Note:
         //   Class name is generated according to its filename.