Detect if we're running an old version of ftw.tika (< 2.0) against new server

Detect if we're running an old version of ftw.tika` (< 2.0) against the [new JAXRS HTTP server](https://github.com/4teamwork/ftw.tika/pull/21) and log a helpful error message.

This PR is against the `1.1.x` branch, which contains the old client implementation that expects a dumb TCP socket server. If for some reason we get a response that looks like HTTP (a `400 Bad Request`, because we sent some random garbage to a server expecting a HTTP request), this is a strong indication that the server is the new JAXRS HTTP server, and we're running an old version of `ftw.tika` against the new server.

We therefore log a message with level `ERROR`, which should end up in Errbit and allow us to upgrade `ftw.tika` accordingly.

@phgross @maethu

/cc @jone