RDMA Live migration support

This is a simple change to allow for live migration of other protocols, including RDMA.

Waiting to be merged with QEMU, we have the 'x-rdma' protocol, where the 'x' means experimental.

I've included both the 'x-rdma' and 'rdma' protocols in the list of hard-coded protocols in the tests, but in general,
there needs to be a more customizable way for the user to extend the list of protocols to that of their choosing.