Comment 1 for bug 1200585

How do you plan to solve this issue?
This is actually common to every quantum API call; the tenants are stored in keystone.

It is my opinion that it won't be a great idea to validate the tenant with keystone for each API call.
Personally, I would consider this bug as invalid.
Only admins can create resourceon behalf of other tenants, and if they create a resource for a non-existent tenant, nobody beyond the admin itself would be able to access that resource.