- Iterate through the deletion list in reverse order so that we

- Iterate through the deletion list in reverse order so that we
  can't delete a backup file that we just created.
- The rename-directory-for-backup heuristic now checks the
  DEL_FORCE_RECURSE flag, not the zap_dir variable.  We also set
  the flag when we recurse so that only the root dir of a deleted
  hierarchy can be missing the flag (and thus be a call from the
  generator).