fix compat with webpack 1

Author: yyx990803

lib/loader.js

@@ -41,11 +41,11 @@ var defaultLang = {
 var excludedPreLoadersRE = /eslint-loader/
 
 function getRawRequest (context) {
-  const clonedContext = Object.assign({}, context, {
+  return loaderUtils.getRemainingRequest({
+    resource: context.resource,
+    loaderIndex: context.loaderIndex,
     loaders: context.loaders.filter(loader => !excludedPreLoadersRE.test(loader.path))
   })
-  delete clonedContext.remainingRequest
-  return loaderUtils.getRemainingRequest(clonedContext)
 }
 
 module.exports = function (content) {