Initial address resolution should not fail fatally

[dsnet]

In this logic:

udptunnel/tunnel.go

Line 131 in f006180

t.log.Fatalf("error resolving address: %v", err)

We try to resolve the remote address at start-up. However, if the network is not initialized yet, then it is possible that this returns an error and the daemon fails fatally early on. This should be more graceful where it still continues into its tunneling logic (even if the remote endpoint is unknown) and defer proper resolution until later.