Don't display unix epoch timestamp coming from wireguard interface

This happens on PSK/pubkey mismatch and is returned by wireguard in
userspace mode.

client/cmd/status.go

@@ -519,7 +519,7 @@ func parsePeers(peers peersStateOutput) string {
  }
 
  lastWireguardHandshake := "-"
- if !peerState.LastWireguardHandshake.IsZero() {
+ if !peerState.LastWireguardHandshake.IsZero() && peerState.LastWireguardHandshake != time.Unix(0, 0) {
  lastWireguardHandshake = peerState.LastWireguardHandshake.Format("2006-01-02 15:04:05")
  }