Remove unused and odd code.

This code was never being used and any use of it would look fairly strange.
For example, it would try to map a object_error::parse_failed to
std::errc::invalid_argument.
Remove unused and odd code.

This code was never being used and any use of it would look fairly strange.
For example, it would try to map a NativeReaderError::file_malformed to
std::errc::invalid_argument.