Logrotate cronjob checks

#### Share the context

All my cronjobs are configured in ```/etc/cron.d/ ``` and everything is working as expected.

#### Description of problem:

The Rule "Ensure Logrotate is running Periodically" fails. As far as the results go, the rule seems to completely ignore the contents of cron.d.

#### Proposed change:

Add cron.d to the list of directories to be checked for the logrotate cron file.