Fixes #6249,BZ1109398: Candlepin proxy routes properly looking up organization.

When the API switched to looking up organization by ID, the Candlepin
proxy routes that required an organization broke since subscription-
manager GUI and CLI pass the organization label and not numerical ID.
Merge pull request #4284 from ehelms/fixes-6249

Fixes #6249,BZ1109398: Candlepin proxy routes properly looking up organi...