message: fix memory leak in micropython_interface
diff: @@ -77,10 +77,15 @@ void micropython_interface::on_setcode(uint64_t _account, bytes& code) {
  FC_ASSERT(false, "unknown micropython code!");
  }
  if (obj != NULL) {
  + if (_itr != pymodules.end()) {
  + delete _itr->second;
  + }
  py_module* mod = new py_module();
  mod->obj = obj;
  mod->hash = fc::sha256::hash( code.data(), code.size() );
  pymodules[_account] = mod;
  + } else {
  + FC_ASSERT(false, "load micropython code failed!");
  }
  }
  