copyImgFiles failed when overlay has subfolders

[demin-han]

Use this workload:
https://github.com/ucb-bar/coremark-workload
put a "hello" subfolder to overlay

Fail report:
TaskError - taskid:/home/FireMarshal/images/firechip/coremark/coremark.img
PythonAction Error
Traceback (most recent call last):
File "/home/miniforge3/envs/firemarshal/lib/python3.10/site-packages/doit/action.py", line 461, in execute
returned_value = self.py_callable(*self.args, **kwargs)
File "/home/FireMarshal/wlutil/build.py", line 603, in makeImage
wlutil.applyOverlay(config['img'], config['overlay'])
File "/home/FireMarshal/wlutil/wlutil.py", line 753, in applyOverlay
copyImgFiles(img, flist, 'in')
File "/home/FireMarshal/wlutil/wlutil.py", line 727, in copyImgFiles
perms = int(oct(os.stat(dirPath).st_mode)[-3:], 8)
FileNotFoundError: [Errno 2] No such file or directory: '/home/FireMarshal/disk-mount/hello'

ERROR: Failed to build workload coremark.json

I think this issue related to Commit c510768.

when check and change permission, the subfolder is still not exist.