title: Webpack dev server attempts to connect to wrong url
body: <p>I'm having trouble with webpack every time i'm trying to give it a chance to be my friend! 
  This time I'm trying to enable Hot Module Reloading with react-hot-loader, webpack &amp; webpack-dev-server but it seems webpack-dev-server is trying to fetch a wrong url in browser.</p>
  
  <p>This is the error from Chrome v50's console:</p>
  
  <pre><code>GET http://public/info?t=1464117419740   net::ERR_NAME_NOT_RESOLVED
  </code></pre>
  
  <p>complete log: </p>
  
  <pre><code>abstract-xhr.js:132 GET http://public/info?t=1464117419740 net::ERR_NAME_NOT_RESOLVEDAbstractXHRObject._start @ abstract-xhr.js:132(anonymous function) @ abstract-xhr.js:21
  index.js:70 [WDS] Disconnected!sock.onclose @ index.js:70EventTarget.dispatchEvent @ eventtarget.js:51(anonymous function) @ main.js:356
  abstract-xhr.js:132 GET http://public/info?t=1464117421752 net::ERR_NAME_NOT_RESOLVEDAbstractXHRObject._start @ abstract-xhr.js:132(anonymous function) @ abstract-xhr.js:21
  </code></pre>
  
  <p>Here is my webpack config:</p>
  
  <pre><code>{
    devtool: 'source-map',
    entry: [
      // 'webpack-dev-server/client?path=http://localhost:3001/', // I have tested it with no luck
      'webpack-hot-middleware/client?path=http://localhost:3001/',
      'webpack/hot/dev-server',
      './index.js'
    ],
    output: {
      path: path.join(__dirname, 'public'),
      publicPath: '/public/',
      filename: 'bundle.js'
    },
    plugins: [
      new webpack.HotModuleReplacementPlugin(),
      new ExtractTextPlugin('index.css', {
        allChunks: true
      })
    ],
    postcss: [
      values,
      cssnext
    ],
    devServer: {
      hot: true,
      inline: true,
      contentBase: './'
    }
    module: {
      loaders: [
        {
          test: /\.js$/,
          loaders: ['react-hot','babel'],
          exclude: /node_modules/
        },
        {
          test: /\.(css)$/,
          exclude: /node_modules/,
          loader: ExtractTextPlugin.extract('style', 'css?modules&amp;importLoaders=1&amp;localIdentName=[name]__[local]___[hash:base64:5]!postcss')
        },
        {
          test: /\.(eot|woff|woff2|ttf|svg|png|jpe?g|gif)(\?\S*)?$/,
          loader: 'file'
        }
      ]
    }
  }
  </code></pre>