Fix issue with % in cron jobs.

Cron evidentally hates % enough that it needs to be escaped.

Ticket: 3741
Fix load of check_space.py

Ticket:	#3752
Add monthly_show_success="NO".

Without the setting the disabled 300.stastistics script monthly nags the user to
enable it -- it will generate an email containing:
---
Posting monthly OS statistics disabled
    set monthly_statistics_enable="YES" in /etc/periodic.conf
---
Merge branch 'post920R'