avoid `Cannot get /` errors if history-api-fallback is enabled

I start webpack dev server with 
```webpack-dev-server -d --history-api-fallback --inline --progress --colors --port 9000```
I expect it to return post-processed ```index.html``` content for all queries including ```/``` or ```index.html```

It works brilliant for ```/index.html``` but it does not work for any other URLs. The thing is that ```historyApiFallback``` implementation only changes ```req.url``` of the request and puts request processing down the interceptors chain. This means that ```this.middleware``` interceptor is not called after request URL is changed. 

My idea is to add ```this.middleware``` once again to let it work correctly. I cannot put this interceptor before  ```this.middleware``` because it might start returning ```/index.html``` for every possible queries. From the other hand, there is no API for `express.js` I aware of to make ```express.js``` restart all interceptors for server-side include. If there is such, the fix could be done on the ```connect-history-api-fallback``` library side