Migration Plugin

To reproduce:

• create and sync rpm_unsigned repo in pulp2
• migrate it
• create a repo copy1 and copy all content from rpm_unsigned
• run a migration with the following plan
• in the new repo version errata will be removed because it is not found in Pulp2Content for a copy1 repo.

{
    "plan": {
        "plugins": [
            {
                "repositories": [
                    {
                        "name": "rpm_unsigned",
                        "pulp2_importer_repository_id": "rpm_unsigned",
                        "repository_versions": [
                            {
                                "pulp2_distributor_repository_ids": [
                                    "rpm_unsigned"
                                ],
                                "pulp2_repository_id": "rpm_unsigned"
                            },
                            {
                                "pulp2_distributor_repository_ids": [
                                    "copy1"
                                ],
                                "pulp2_repository_id": "copy1"
                            }
                        ]
                    }
                ],
                "type": "rpm"
            }
        ]
    },
}

Alternatively, if you run for the second migration the migrate-all plan, the new repository will lack errata as well.

We likely need to work around it in the migration plugin, since updating _last_updated date for a copy in pulp 2 will cause problems in pulp2 world - publish will be operational for all repositories which contains an erratum if that erratum has been copied (Katello uses copy heavily).