Handle situation when ip changes on the vpn connection

[skrupler]

Rtorrent stops working when bound to an IP not associated with the actual IP on the nic of netns.
This issue happens when the IP on the connection changes
but rtorrent tries to bind to the old IP
must be circumvented somehow.

Steps to reproduce:

1. run rtorrent on an openvpn connection for a while
2. wait for ip to change
3. error message appears: Error: Tracker: [Failed binding local connection end]

Solution

rtorrent probably needs to restart / rebind somehow.