Clear tor_peer_group_store.protobuf if connections fails

[djing-chan]

In case users fail to connect to the network it might be that the peers in tor_peer_group_store.protobuf are too old and most offline.
We should improve the peer management to avoid that but one option at least at failed startup might be to clear that when shut down the app, or at least to add a button to clear at the settings (better to do it automatically IMO).