message: fix unpack vm_type
diff: @@ -664,6 +664,8 @@ std::istream& operator>>(std::istream& in, wasm_interface::vm_type& runtime) {
  runtime = eosio::chain::wasm_interface::vm_type::wavm;
  else if (s == "binaryen")
  runtime = eosio::chain::wasm_interface::vm_type::binaryen;
  + else if (s == "wabt")
  + runtime = eosio::chain::wasm_interface::vm_type::wabt;
  else
  in.setstate(std::ios_base::failbit);
  return in;
  