Enhance TariffSynchronizer logger spec

Should clean class variable in outer block
Revert "Merge pull request #83 from alphagov/disable-cron"

This reverts commit c670775ee66a774bf0e991dd35224a5d9ba5ee21, reversing
changes made to c386fcf29a448eea1b46bc6cee4b95a933a1fc35.