CreateOrder does not capture errors correctly

[David Tai]

CreateOrder doesn't error on these types of errors:

{"type":"http://developer.mailchimp.com/documentation/mailchimp/guides/error-glossary/","title":"Invalid Resource","status":400,"detail":"The resource submitted could not be validated. For field-specific details, see the 'errors' array.","instance":"","errors":[{"field":"id","message":"cannot be empty"}]}