Docker images are not deleted from registry when a project is removed (resulting in orphaned images)

In GitLab CE 8.8.4, when deleting a project that contains a Docker image in the GitLab Docker registry, the repository is not cleaned up.
For instance, I have a group named company with a project and Docker image named ubuntu-14.04.
I am logged in to the registry on GitLab and succesfuly pushed the image: docker push registry.example.com/company/ubuntu-14.04.

Next, when I delete the project ubuntu-14.04, on filesystem level on the GitLab-host at /var/opt/gitlab/gitlab-rails/shared/registry/docker/registry/v2/repositories/ and ../blobs nothing is removed! Not in "repositories" nor in "blobs".

So over time the directory /var/opt/gitlab/gitlab-rails/shared/registry/docker/registry/v2/ will be "polluted" with historical, but useless data and hence heaps of disk space is wasted on orphaned images.

Has this been accounted for?
And if so or not, how can we deal with this situation? For example, use special API sequences as mentioned on StackOverflow: http://stackoverflow.com/questions/25436742/deleting-images-from-a-private-docker-registry but are these available for GitLab yet?

Thank you!