Consuming remaining jobs and correct approvals_required

CE backport: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24881

What does this MR do?

This is consisted of two fixed:

MigrateApproverToApprovalRulesInBatch sidekiq job GRPC::NotFound error https://gitlab.com/gitlab-org/gitlab-ee/issues/9518

20190114040405_consume_remaining_migrate_approver_to_approval_rules_in_batch_jobs.rb

• Consumes remaining jobs
• Fix exception of cases where project's repository is missing.

This is estimated to take around 10 minutes in total on production:

• searching for target MRs: 2 minutes
• migrating those MRs: 8 minutes

Fix approvals_required being zero, follow up of !9143 (merged)

20190114040404_correct_approvals_required.rb

A data clean up after the fix.
Some MR rules might have 0 as approvals_required where it should have been the project's `approvals_required'. Find those and update to project approval rate.

The affected rows are 240, and the migration will take 3 seconds.

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9143 #8647 (closed)

Does this MR meet the acceptance criteria?

• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• EE specific content should be in the top level /ee folder
• For a paid feature, have we considered GitLab.com plans, how it works for groups, and is there a design for promoting it to users who aren't on the correct plan?
• Security reports checked/validated by reviewer