Fix issue with private flavors not being visible on refresh

https://bugzilla.redhat.com/show_bug.cgi?id=1117972

@chessbyte Please review.
Re: `process_flavor_collection`...I like the idea, but the pattern is pervasive, so I'll keep it the way it is for consistency.  Nearly every `process_collection` call should just be changed to `process_collection(colllection, key, method_name)`, and not do the block thing over and over.