message: das.cli: Fix warnings.
diff: @@ -354,7 +354,7 @@ namespace elle
  {
  return elle::from_string<bool>(v);
  }
  - catch (std::invalid_argument)
  + catch (std::invalid_argument const&)
  {
  throw OptionValueError(this->_option, v, "invalid boolean");
  }
  @@ -388,11 +388,11 @@ namespace elle
  {
  return to_int<I>(v, this->_option);
  }
  - catch (std::invalid_argument)
  + catch (std::invalid_argument const&)
  {
  throw OptionValueError(this->_option, v, "invalid integer");
  }
  - catch (std::out_of_range)
  + catch (std::out_of_range const&)
  {
  throw OptionValueError(this->_option, v, "integer out of range");
  }
  