After blocking a POST request we are trying to read next request but data was not read to end

https://github.com/AdguardTeam/AdguardForAndroid/issues/332

In case if request has entity body, we should make response with a "Connection: close".

I am not sure if we has this bug in Windows version (as I remember we read request body just in case).
