Comment 0 for bug 1546149

Environment:
 - I'm using Liberty (on RDO)
 - I'm using the angularjs launch instance.
 - I have a flavor with disk = 0 GB.
 - I use Ceph RBD backend and always create volume on instantiation (If I don't, the actual image size should be used when creating temporary volume etc of RBD)

Work flow:
 - I click Yes to Create volume
 - I pick an image with min_disk 1,
 - I see warning that my volume size must be minimum 2 (don't mind the GB/GiB inconsistency)
 - I up the volume size to 2 GB
 - I continue to selecting flavor dialogue panel
 - Any flavor with disk size = 0 GB is grayed out, hitting the warnings at https://github.com/openstack/horizon/blob/master/openstack_dashboard/dashboards/project/static/dashboard/project/workflow/launch-instance/flavor/flavor.controller.js#L302

Expected behaviour:
 - since I am creating a volume and defining its size,
 - and since that the size of the volume I'm creating has already been verified,
 - i expect that disksize = 0 GB in a volume should be allowed in the flavor checking (code line referenced above)

Disk size = 0 GB is a special value, according to for instance: http://docs.openstack.org/openstack-ops/content/flavors.html .
And it makes sense (to me at least) that I should be able to detach disk size information from flavors when using Ceph / RBD and I as the user always configure the volume.

And if I do not set the volume size, and eg boot from image, Nova, Glance and Ceph should take care of instantiating a snap or similar of the original image to its predefined size already - "no user input required".

I.e. flavor disk size = 0 GB should mean that either the source image or the volume size applies for the volume to be created (or not, in the boot from image case).