Review 26192

C. Thomas Tyler
Crontab cleanup:
* Removed bogus refs to deleted scripts.
* Commented out optional maintenance script, and updated comment
to indicate when to use them.
* Cleaned up and corrected comments.
* Changed crontab schedule to optimize for most common use case,
e.g. running checkpoints weekly rather than monthly (typically done
only at extreme scale).
Tip: Use n and p to cycle through the changes.