Ma/org endpoint

Harden org creation endpoint for failure.

@opscode/server-team 
No, that fails with 409 if there's a name conflict. This is the case where there was no org record, we failed in the create process, but somehow left an org record with that name. We'd need a finer grained response from creation to distinguish that. Even if we can't make this process fully transactional, it might be worthwhile to at least try to wrap some of these in transactions.