Docker Support

Sync the following docker repo
feed: https://quay.io/
upstream_name: openshift-release-dev/ocp-release

Pulp Crane

Check out the following output when syncing v1 content

$ curl --head -L https://<fqdn>:5000/v2/default_organization-custom-ocp/manifests/4.0.0-0
HTTP/1.1 302 FOUND
Date: Mon, 04 Feb 2019 16:29:14 GMT
Server: Apache/2.4.6 (Red Hat Enterprise Linux)
Content-Length: 437
Location: https://<fqdn>/pulp/docker/v2/fe117c3c-5820-4406-ad34-8404062b8458/manifests/1/4.0.0-0
Content-Type: text/html; charset=utf-8

HTTP/1.1 200 OK
Date: Mon, 04 Feb 2019 16:29:15 GMT
Server: Apache/2.4.6 (Red Hat Enterprise Linux)
Last-Modified: Wed, 30 Jan 2019 16:28:40 GMT
ETag: "e5e-580af6711a0c7"
Accept-Ranges: bytes
Content-Length: 3678
Docker-Distribution-API-Version: registry/2.0

Quay:
Now compare it to the same in quay

$ curl --head -L https://quay.io/v2/coreos/etcd/manifests/latest
HTTP/2 200
server: nginx/1.14.2
date: Mon, 04 Feb 2019 16:29:41 GMT
content-type: application/vnd.docker.distribution.manifest.v1+prettyjws
content-length: 6655
docker-content-digest: sha256:5b6691b7225a3f77a5a919a81261bbfb31283804418e187f7116a0a9ef65d21d
x-frame-options: DENY
strict-transport-security: max-age=63072000; preload

Notice how content-type is set to application/vnd.docker.distribution.manifest.v1+prettyjws in the case of quay, while its blank for pulp-crane.

This causes issues in clients pulling this information.