Description of problem:

Applying the 'sku' parameter (ex: /candlepin/owners/5394945?sku=SER0232US) always returns an empty set.


Version-Release number of selected component (if applicable): candlepin-0.9.51.15-1


How reproducible: Always


Steps to Reproduce:
1. Attach a subscription to a consumer, noting the SKU
2. For that owner, query for consumers, filtering on that SKU using necessary attribute (?sku={SKU})


Actual results: 1 consumer should be returned

Expected results: 0 consumers returned


Additional info: I believe this is pending code review, waiting to be merged