configurable audit cron and ensure only one

Prior, the cronjobs were being set if there was more than one scheduler node.
This logic will ensure only one node at a time will be set to run the audit.
Cron job is also now configurable to preference.  Prior was setting to every
minute, which is more frequent than necessary.

Change-Id: I27b760b9260963bad3459bf2eb220e2c2966eb0f