Description of problem:

Sycing custom yum repo from git fails with: Specification mandates value for attribute crossorigin

How reproducible:
Always:

 Configure custom yum repo on satellite using the below upstream url
https://github.com/mydumper/mydumper_repo/tree/bb560b41211558060ab220d9f2e1f6e285125794/yum/8

The error encountered:
Parse error '/var/lib/pulp/tmp/1437@satellite.example.com/tmpqpnw766y/tmp0rxqiv10-repomd.xml' at line: 24 (Specification mandates value for attribute crossorigin
)
Expected behavior:
[Describe what should be happening instead]

Repsync should complete fine.

Business Impact / Additional info: