SubFS: make removedir() more robust to concurrent deletion of files
SubFS: make removedir() more robust to concurrent deletion of files

rivenz/pyfilesystem,Konubinix/pyfilesystem,PyFilesystem/pyfilesystem,pmitros/pyfs,piranna/pyfilesystem,zopyx/pyfilesystem,pmitros/pyfs,pombreda/pyfilesystem,flying-circus/pyfilesystem