Fix race condition where socket is closed on 'connection' event
Fix race condition where socket is closed on 'connection' event

If the connection has already been closed before the `connect` event is
fired,
then `remoteAddress` will not be available, and we can't use this
connection.
- Node.js issue: https://github.com/nodejs/node-v0.x-archive/issues/7566
- WebTorrent issue: https://github.com/feross/webtorrent/issues/398

arestov/bittorrent-swarm