Fix instance list for instances running multiple times

If for some reason (e.g. failed migration) one instance is running
on multiple nodes the output can become inconsistent. To get that error
and make it consistent between runs we make the call on the secondary
too and look if it's running there. If so we report the instance as
ERROR_wrongnode.

Signed-off-by: René Nussbaumer <rn@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>