Remove the rest of `trigger_schedule` related codes
Description
A few trigger_schedule
related codes remain. Let's remove.
Proposal
trigger_schedule_attributes: [:id, :active, :cron, :cron_timezone, :ref]
https://gitlab.com/gitlab-org/gitlab-ce/blob/master/spec/factories/ci/triggers.rb#L6
factory :ci_trigger_for_trigger_schedule do
Links / references
/cc @zj