Don't handshake if there is no key yet; first start on Ethereal

peer.go

@@ -531,13 +531,16 @@ func (p *Peer) Stop() {
 }
 
 func (p *Peer) pushHandshake() error {
-	pubkey := ethutil.GetKeyRing().Get(0).PublicKey
+	keyRing := ethutil.GetKeyRing().Get(0)
+	if keyRing != nil {
+		pubkey := keyRing.PublicKey
 
 		msg := ethwire.NewMessage(ethwire.MsgHandshakeTy, []interface{}{
 			uint32(ProtocolVersion), uint32(0), p.Version, byte(p.caps), p.port, pubkey[1:],
 		})
 
 		p.QueueMessage(msg)
+	}
 
 	return nil
 }