Otherwise, the nagios config will get regenerated and nagios gets
reloaded before all checks are registered by a check_mk inventory.

- Related: #6873

After upgrading the platform, there might be old check_mk checks
registered on the monitor hosts. We now run a check_mk inventory
on every run that also purged old non-existng checks.

- Resolves: #6873

Change-Id: I20a28ae77c98071aefc1933e0ea73e5f3b895acb

Shorewall in jessie doesn't come with a proper unit file, and
as a result, it doesn't properly start with systemd.

To solve this, we provide the systemd unit file that comes with stretch,
add a systemd submodule that provides the exec resources needed for when
systemd units or configuration files are changed

Change-Id: I861fa951835928b4741abfbf969adcee4b8f147b

- ignore puppet lint error about inheriting from different namespace

If clamd is not running, the helpful cronjob tries to start it again,
but the way it is being started can only be run as root, and the cronjob
is run as the clamav user, so you get an error on each cron run. This
fixes that problem

Change-Id: I4cdb29dc651bee8a2eef1655ad4748d885afae0f