Ignore some more harmless messages that appear to be caused by
someone connecting to the server and then disconnecting without
trying to authenticate (such as when they realize their Kerberos
ticket is expired or doesn't exist).

Don't single out the specific accounts that Nessus checks, but instead
skip all the errors about disconnecting due to too many authentication
failures.

Add additional ignore patterns for failed ssh logins from IT Services
staff.

error: ssh_msg_send: write appears to be from a network connection
error.  It was logged on git.stanford.edu.  I don't think we care
about it.

This is the (old) master branch along with the fixes to the
cron file permissions that Russ made.