[8.3rc1] Archive API endpoint broken

Hey Guys,

It looks like something might be broken with the API, I can't find if this is intended or really broken or just my fault (self-hosted community edition).

When requesting https://git.domain.com/api/v3/projects/group%2Fproject/repository/archive?sha=bhadkfhsgfkydgfsyegfskyfgsk a tar should be returned, now however I get JSON:

{
    "RepoPath": "/home/git/repositories/group/project.git",
    "ArchivePrefix": "project-bhadkfhsgfkydgfsyegfskyfgsk-a76b4b0521fe1551bfa12c4e820244af65852387",
    "ArchivePath": "/home/git/gitlab/shared/cache/archive/project.git/project-bhadkfhsgfkydgfsyegfskyfgsk-bhadkfhsgfkydgfsyegfskyfgsk.tar.gz",
    "CommitId": "bhadkfhsgfkydgfsyegfskyfgsk"
}

(I changed the commit hashes and pathnames for obscurity)