Some AMIs are missing the 'apt-daily-upgrade.timer' job and are failing.

See OPS-2365

This appears to have come in when we updated our base AMI.

Checking for them is generally a waste of time these days.
We also now default to applying security updates on devstacks and
we do them in production.  We may enable them everywhere in a future
release, but that will require more updates.

This allows for security updates to be applied during artifact creation,
but not applying other updates.

The headers were pointing to the old github wiki. Since we've officially
moved to Confluence, these links should be updated.

Fixes to support auto deployment of read replicants

updating var names

extra /

updating host var

extra /