DcsSocketIOBrowser.on "disconnect" is triggered more than once when server is not reachable

[ceremcem]

Reproduction:

1. Let the client connect to the DCS server
2. Stop DCS server
3. Verify that DcsSocketIOBrowser.on "disconnect" event is triggered periodically.

Possibly responsible line:

aktos-dcs-node/services/dcs-proxy/protocol-actor/client.ls

Line 211 in bb5a10d

@connected = no