message: Resolve 2 redundant_field_names lint warnings
diff: @@ -1010,8 +1010,8 @@ fn json_stderr(line: &str, package_id: &PackageId, target: &Target) -> CargoResu
  .map_err(|_| internal(&format!("compiler produced invalid json: `{}`", line)))?;
  machine_message::emit(&machine_message::FromCompiler {
  - package_id: package_id,
  - target: target,
  + package_id,
  + target,
  message: compiler_message,
  });
  } else {
  