Client are disconnected only on shutdown

`btcwallet` is not letting go of disconnected clients until it's shutdown:

    13:53:01 2014-08-01 [INF] BTCW: New websocket client 127.0.0.1:47448
    13:53:01 2014-08-01 [INF] BTCW: New websocket client 127.0.0.1:47449
    13:53:10 2014-08-01 [WRN] BTCW: Reached threshold of 25 concurrent active clients

    ^C13:53:23 2014-08-01 [INF] BTCW: Received SIGINT (Ctrl+C).  Shutting down...
    13:53:23 2014-08-01 [WRN] BTCW: Server shutting down
    13:53:23 2014-08-01 [INF] BTCW: Disconnected websocket client 127.0.0.1:47431
    13:53:23 2014-08-01 [INF] BTCW: Disconnected websocket client 127.0.0.1:47426