message: op-node: error if user explicitly sets p2p key path to empty path
diff: @@ -246,6 +246,9 @@ func loadNetworkPrivKey(ctx *cli.Context) (*crypto.Secp256k1PrivateKey, error) {
  return parsePriv(raw)
  }
  keyPath := ctx.GlobalString(flags.P2PPrivPath.Name)
  + if keyPath == "" {
  + return nil, errors.New("no p2p private key path specified, cannot auto-generate key without path")
  + }
  f, err := os.OpenFile(keyPath, os.O_RDONLY, 0600)
  if os.IsNotExist(err) {
  p, _, err := crypto.GenerateSecp256k1Key(rand.Reader)
  