message: Fix build_doc test
diff: @@ -123,8 +123,10 @@ mod test {
  let doc = build_doc("rand", None, None);
  assert!(doc.is_ok());
  - let doc = doc.unwrap();
  - remove_dir_all(format!("{}-{}", doc.manifest().name(), doc.manifest().version())).unwrap();
  + let root_path = Path::new("cratesfyi");
  + assert!(root_path.join("doc").join("rand").exists());
  +
  + remove_dir_all(root_path).unwrap();
  let doc = build_doc("SOMECRATEWICHWILLBENVEREXISTS", None, None);
  assert!(doc.is_err());
  