Rather than just querying a single remote node, query them all, and accomodate remote nodes that might be running older versions than ourselves, provided we can find someone who is running the same as us.

I did try just limiting Nodes to Nodes with the rabbit process running on them. That seemed to break the tests, and trying to figure out why by looking at rabbit_mnesia made me want to slit my wrists and other body parts. Thus I wrote more code instead.
Undo some changes.
Remove unnecessary test.
Merge bug25899