Version 3 ram_load depends on ram_addrs, which are not stable.  Version 4
was introduced in 0.13 (and RHEL 6), so this means live migration from 0.12
and earlier to 1.1 or later will not work.
Reviewed-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>