CI/CD: Fix `scratch` field in ci.container-image.test.complete messages
Following up https://pagure.io/waiverdb/pull-request/282.
This PR changes the pagure polling job to pass the original branch name
rather than commit ID to `waiverdb-dev` job on master branch changes.
`waiverdb-dev` then passes commit ID to downstream container build and integration test jobs
to ensure the exact same commit is processed.