COLO: migrate COLO related info to secondary node

We can determine whether or not VM in destination should go into COLO mode
by referring to the info that was migrated.

We skip this section if COLO is not enabled (i.e.
migrate_set_capability colo off), so that, It doesn't break compatibility
with migration no matter whether users configure the --enable-colo/disable-colo
on the source/destination side or not;

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Amit Shah <amit@amitshah.net>