message: Use a single immutable env reference
diff: @@ -255,22 +255,17 @@ fn account_for_externally_used_gas_impl<S: Storage, Q: Querier>(
  env: &Env<S, Q>,
  used_gas: u64,
  ) -> VmResult<()> {
  - // WFT?!
  - let env1 = env.clone();
  - let env2 = env.clone();
  - let env3 = env.clone();
  -
  - env1.with_context_data_mut(|context_data| {
  + env.with_context_data_mut(|context_data| {
  let gas_state = &mut context_data.gas_state;
  - let wasmer_used_gas = gas_state.get_gas_used_in_wasmer(get_gas_left(&env2));
  + let wasmer_used_gas = gas_state.get_gas_used_in_wasmer(get_gas_left(env));
  gas_state.increase_externally_used_gas(used_gas);
  // These lines reduce the amount of gas available to wasmer
  // so it can not consume gas that was consumed externally.
  let new_limit = gas_state.get_gas_left(wasmer_used_gas);
  // This tells wasmer how much more gas it can consume from this point in time.
  - set_gas_left(&env3, new_limit);
  + set_gas_left(env, new_limit);
  if gas_state.externally_used_gas + wasmer_used_gas > gas_state.gas_limit {
  Err(VmError::GasDepletion)
  