message: Avoid unwrap when determining proper shell to use
diff: @@ -208,7 +208,10 @@ fn execsh(config: &Config) -> ! {
  let pw = get_pw_entry(&mut buf);
  let shell = match config.shell() {
  - Some(shell) => shell.to_str().unwrap(),
  + Some(shell) => match shell.to_str() {
  + Some(shell) => shell,
  + None => die!("Invalid shell value")
  + },
  None => pw.shell
  };
  