SilcBool silc_sftp_fs_memory_del_dir(SilcSFTPFilesystem fs, void *dir);

    Deletes a directory indicated by the `dir'. All files and
    subdirectories in this directory is also removed.  If the `dir' is
    NULL then all directories and files are removed from the filesystem.
    Returns TRUE if the removing was success. This is the only way to
    remove directories in memory file system. The filesystem does not
    allow removing directories with remote access using the filesystem
    access function sftp_rmdir.