FOSS broken because Gitlab::BackgroundMigration::UpdateVulnerabilityOccurrencesLocation::Occurrence is not defined
Job [#1774415648](https://gitlab.com/gitlab-org/gitlab-foss/-/jobs/1774415648) failed for gitlab-foss@11c2b8eff6ca5360fb0f732b23b764d2a0b81be5:
```
# --- Caused by: ---
# NameError:
# uninitialized constant #<Class:0x00007ffac7c58130>::Occurrence
# ./db/post_migrate/20211102114802_update_vulnerability_occurrences_location.rb:11:in `up'
```
issue