Traceback (most recent call last):
  File "/usr/share/samba/setup/upgradeprovision", line 1719, in <module>
    backup_provision(paths, backupdir)
  File "/usr/share/samba/setup/upgradeprovision", line 1526, in backup_provision
    shutil.copytree(paths.sysvol, os.path.join(dir, "sysvol"))
  File "/usr/lib/python2.7/shutil.py", line 169, in copytree
    names = os.listdir(src)
TypeError: coercing to Unicode: need string or buffer, NoneType found