conf: add cpu check attribute to ABI check
Different check values are not ABI compatible. For example
if on migration we change 'full' to 'partial' then guest cpu
on destination can be different.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>