Deep create log dir
It was reported that program crashed if log dir needs deep mkdir.  So
now deep create it.
@@ -44,7 +44,7 @@ fn init_log_file(file: &mut Write) {
impl Logger {
pub fn new(log_dir: PathBuf) -> Logger {
- let _ = fs::create_dir(&log_dir);
+ let _ = fs::create_dir_all(&log_dir);
let debug_logs = {
let mut log_dir = log_dir.clone();
