Removed old plugins from webpack config.

config/webpack.production.config.js

@@ -58,7 +58,7 @@ module.exports = {
     tls: 'empty'
   },
   plugins: [
-    new webpack.NoErrorsPlugin(),
+    new webpack.NoEmitOnErrorsPlugin(),
     new webpack.optimize.CommonsChunkPlugin({ name: 'vendor', filename: '[chunkhash].vendor.js' }),
     new WebpackCleanupPlugin(),
     new webpack.DefinePlugin({
@@ -78,7 +78,6 @@ module.exports = {
     new HtmlWebpackPlugin({
       template: './src/template.html',
       title: 'Maputnik'
-    }),
-    new webpack.optimize.DedupePlugin()
+    })
   ]
 };