
This disambiguates the description on the server.image parameter.
If the server is booted from volume (where boot from volume means
there is a bdm with boot_index=0 and destination_type=volume),
then the server.image will be an empty string [1] otherwise it
will be a dict.
[1] 2f0f8b8cf1/nova/api/openstack/compute/views/servers.py (L540)
Change-Id: Ia1ecd39a5636fa5a35cdbcafc03828b2925a9033