Revert "Add Errbit notification to scheduled publishing worker"

The automatic exception handling in errbit is working.  This explicit
notification causes duplicates in Errbit.

This reverts commit ed241050caa36ebd5176a5cdbb5a3fa5c3bd4db4.
Merge pull request #189 from alphagov/remove_explicit_sidekiq_error_handling

Revert "Add Errbit notification to scheduled publishing worker"