Open Stack

Hi, Paul/Dan
	For the extra_resource (refer to Dan's comments in https://review.openstack.org/#/c/60258/ for more information), I created a patch set https://review.openstack.org/#/q/status:open+project:openstack/nova+branch:master+topic:extra_resources,n,z and want to get some feedback.

	This patch set makes the extra_resources a list of object, instead of opaque json string. How do you think about that?

	However, the compute resource object is different with current NovaObject, a) it has no corresponding table, but just a field in another table, and I assume it will have no save/update functions. b) it defines the functions for the object like alloc/free etc. Not sure if this is correct direction.

Thanks
--jyh