Deleting a user doesn't remove his SSH key from .ssh/authorized_keys
Created by: fpavageau
Of course the user will get "acces denied" when he tries to access the repositories, but still.
Then, if the user is added again and reuploads the same key, you get duplicate keys with different key-xxx parameters to gitlab-shell and since the first (and oldest) one is probably used, the user will keep on getting "access denied".