securityonion-rule-update: sensor-only boxes running salt shouldn't try to copy /etc/cron.d/rule-update

[dougburks]

Ryan Peck found an issue with the recent securityonion-rule-update release:
https://groups.google.com/d/topic/security-onion/6-WYvNJbyaY/discussion

Here are the changes:
Security-Onion-Solutions/securityonion-rule-update@6762b57

Specifically, see the new postinst:
https://github.com/Security-Onion-Solutions/securityonion-rule-update/blob/6762b5764dda0d7ca9e99cff8d54a619b9324bdf/debian/postinst

[dougburks]

Submitted for testing:
https://groups.google.com/d/topic/security-onion-testing/Awm2W1LAlm4/discussion

[dougburks]

Published:
http://blog.securityonion.net/2015/04/new-securityonion-rule-update-package_28.html