Description of problem:
Cinder allows users to upload encrypted volumes as images.  Nova does not support direct boot of such images; the workflow is that such images should only be used for boot-from-volume.  If a user tries the unsupported path, however, Nova will boot an instance that goes 'active' and is unusable.  It would be better if the instance did not go 'active'.  (Ideally this could be rejected at the API layer as some kind of 4xx.)


Version-Release number of selected component (if applicable):
Observed in 16 (Train), 

How reproducible: always


Steps to Reproduce:
1. in cinder: create an volume V-1 of an encrypted volume type
2. in cinder: upload V-1 as an image to Glance; call this image I-1
3. in nova: boot an instance S-1 from I-1

Actual results:
S-1 goes 'active'

Expected results:
Since this isn't a supported action, S-1 should should not go 'active' (either by never being created, or by going to some other appropriate status).