893596 - fixing repobinding to be specific to a single repo

Previously katello-agent sent up the repo_id from the redhat.repos
file.  This however was the cp_id of the content and in no way 
uniquely identified the repo.  Now katello-agent sends up the baseurl:

https://github.com/Katello/katello-agent/pull/2

which we can use to uniquely identify the repo.