Cowboy 0.10.0 support and small fix

Commits for cowboy 0.10.0 support.
And fix for JsessionidCookie.test_xhr sockjs-protocol test. (passed now)

After changes sockjs-protocol tests shows (failures=1, errors=5) all errors and failures in WebsocketHixie76 protocol test:
- WebsocketHixie76.test_broken_json()
- WebsocketHixie76.test_close()
- WebsocketHixie76.test_empty_frame()
- WebsocketHixie76.test_reuseSessionId()
- WebsocketHixie76.test_transport()
- WebsocketHixie76.test_haproxy()
All this errors happens because after returning {upgrade, protocol, cowboy_websocket} in cowboy_handler, Cowboy server answers with error 400. I have no idea why it happens.

But on client side everything works. All sockjs-client tests in Chrome, Safari and Firefox 100% passed.