crust_peer fails to stop

[vinipsmaker]

Not the first time it happens ( #277 #141 ).

[vinipsmaker]

It's working again. Not sure which commit fixed it, but must have been work from @inetic.

[vinipsmaker]

It's failing again.

How to reproduce

1. Open a single crust_peer instance.

2. Do not connect to any other node. You may see:

      Running `target/debug/examples/crust_peer`
      Listening on ports Tcp(V4(0.0.0.0:5483))
      Enter command (stop | connect <endpoint> | send <endpoint> <message>)>
   

   You might also see:

   Didn't bootstrap to an existing network - this may be the first node of a new network.
   

3. Enter stop.

4. crust_peer doesn't stop.

A hint to solve this issue. The hanged/hanging crust_peer instance will gracefully stop if you, now, start another crust_peer instance that will automatically connect (through beacon) to the previous instance. This second instance won't have any trouble to execute the stop command.

[inetic]

Fixed here 20965f1