message: fix(vfs) Do not unwrap in `remove_dir`.
  In 2 cases:
  1. When the path has a parent that doesn't exist,
  2. When the directory doesn't exist.
diff: @@ -154,14 +154,14 @@ impl crate::FileSystem for FileSystem {
  let file = path.file_name().unwrap();
  let mut inner = self.inner.lock().unwrap();
  - let node = inner.get_node_at_mut(parent).unwrap();
  + let parent_node = inner.get_node_at_mut(parent);
  - match node {
  - Node::Directory { children, .. } => {
  + match parent_node {
  + Some(Node::Directory { children, .. }) => {
  let name = file.to_str().unwrap();
  - match children.get(name).unwrap() {
  - Node::Directory { children, .. } => {
  + match children.get(name) {
  + Some(Node::Directory { children, .. }) => {
  if !children.is_empty() {
  return Err(FsError::DirectoryNotEmpty);
  }
  