Add supported_instances to get_available_resource to all virt drivers

Add 'supported_instances' to the function get_available_resource for all
virt drivers (except libvirt which is done separately). This will help
make image_props_filter work without the RPC broadcast capabilities.

Part of bp no-compute-fanout-to-scheduler

Change-Id: If9eee203b3cbb12963dc55e4215d206cb5d81264
Merge "Add supported_instances to get_available_resource to all virt drivers"