jobs that lose ci-director stanzas cause infinite builds

functional-assess-cloud-kill-manual briefly had a ci-director stanza because it was cloned from functional-assess-cloud-manual.

This caused assess-cloud-kill-manual to be added to a number of revision builds. This caused ci-director to trigger builds for it. But since it no longer had a ci-director stanza, the build was never recorded. Once the build had completed, it was a candidate to be triggered again.

This caused the revision builds to be considered "active" long after their last legitimate build had completed.

I fixed this by manually deleting assess-cloud-kill-manual from the relevant ~/.config/ci-director-start-builds/revision-build*.json files.

Several things should be considered:
- start-builds should not build anything that lacks a ci-director stanza
- entries in revision build files should not remain active if their actual job has no ci-director stanza.