Revert "Merge branch '3062-improve-project-cache' into 'master'"
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23135/diffs was reverted in 11.6, but it was not reverted in master. As a result, canary and production don't agree on the cache key, leading to missing branches and causing https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/5704 again.