Hi Mike,
This strikes me as more of a vdsm problem than ovirt-node directly. Once node is registered to engine, we hand over all control of libvirt and networking (among other things) to the engine to manage. If migration is failing due to some setting on the node, then vdsm should probably be changing that setting when it comes online.
I'm adding the vdsm-devel list to get them to look at this issue.
Thnx Mike hope to get it solved soon.