Listening sockets not always correctly cleaned up on team exit.

[anevilyak]

Occasionally the network stack appears to not properly clean up when a team exits. On several instances I've observed a case where Vision crashed, and after exit netstat indicated that port 113 was still being listened on despite the team being gone (socket was in state LISTEN). Possibly an issue but less problematic were 3 connections to irc servers still sticking around in close-wait state. 45 minutes later this was still the case for all the mentioned sockets though, and only a reboot appeared to fix it. Uncertain as to the most appropriate component so assigning to stack for now.

[waddlesplash]

This might have improved following hrev54256.