Inconsistent behavior when 2nd network interface goes up or down

When I’m using both an Ethernet cable and a Wi-Fi, every change in connectivity has a different behavior:

• While the Wi-Fi remains connected
  • When the Ethernet cable goes down: the Tor connectivity breaks for a very long time (more than 60 s)
  • When the Ethernet cable goes up: the Tor connectivity breaks only for 5-10 s
• While the Ethernet cable remains connected
  • When the Wi-Fi goes down: the onion icon goes off but the Tor connectivity is not interrupted
  • When the Wi-Fi goes up: the onion icon goes on and the Tor connectivity is not interrupted

We should fix:

• The break of connectivity when the Ethernet cable goes down but Wi-Fi remains connected
• The inconsistency in the display of the onion icon when the Wi-Fi goes down but the Ethernet cable remains connected

Original created by @sajolida on 16900 (Redmine)