RPM Support

Ticket moved to GitHub: "pulp/pulp_rpm/2292":https://github.com/pulp/pulp_rpm/issues/2292

1. "packages" field on variants may not match with reality in the mirror case. You can see that the "repository" and "packages" fields for the "variant-External" variant which previously had both the repository and packages listed as "../rpm-signed/" now maps to "External" and "External/Packages", respectively. But in the event of mirror sync, this is incorrect.

Likewise, the Land variant is wrong - but this may be a fixture issue. There is no such "Packages" directory. https://fixtures.pulpproject.org/rpm-distribution-tree/variants/land/

 ('change', 'variant-Land.packages', ('Packages', 'Land/Packages')),
 ('change', 'variant-Land.repository', ('variants/land', 'Land')),
 ('change',
  'variant-External.packages',
  ('../rpm-signed/', 'External/Packages')),
 ('change', 'variant-External.repository', ('../rpm-signed/', 'External'))]

2. The order of the "variants" is different from the original - since productmd sometimes places significance on the first variant in the list, this could possibly have an impact in some cases.

[('change', 'general.variants', ('Land,Sea,External', 'External,Land,Sea')),
 ('change', 'tree.variants', ('Land,Sea,External', 'External,Land,Sea')),

test_publish.py::DistributionTreeMetadataTestCase needs to be updated for both of these