Add log file to puppet_node_clean cron
Add log file to puppet_node_clean cron

The cron job is sending the output to the mail service, but this
is not configured properly on AWS yet. This chnage sends the
puppet_node_clean output to a log file, that is going to be rotated
by the default govuk-logs logrotate configuration.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet