refine expected_images, add cloud images
    
    So my anal instincts kicked in and this makes expected_images
    meet my usual ludicrously over-engineered standards: it should
    now be more or less correct for EVERY FEDORA EVER. You can
    check if Fedora 10 was missing any expected deliverables if you
    like!
    
    This also adds expected Cloud images (for post-F20 releases):
    for now we're expecting base and Atomic disk images for both
    Intel arches. This can change on request.