message: Fix mutable_borrow_reservation_conflict warning.
diff: @@ -791,7 +791,8 @@ impl Execs {
  pub fn cwd<T: AsRef<OsStr>>(&mut self, path: T) -> &mut Self {
  if let Some(ref mut p) = self.process_builder {
  if let Some(cwd) = p.get_cwd() {
  - p.cwd(cwd.join(path.as_ref()));
  + let new_path = cwd.join(path.as_ref());
  + p.cwd(new_path);
  } else {
  p.cwd(path);
  }
  