Abstracted from qmp_migrate_set_parameters().

Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1500349150-13240-6-git-send-email-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>