The previous behavior of root_ip meant that whatever /32 hosted by the device
that got listed first would be chosen as the root_ip. If the device only
serves one /32 this works fine, but if there are multiple /32s we could easily
pick the one that is not the intended address meant for management.
Instead, before we pick whatever /32 may exist, we now try to pick the /32 that
is also the OSPF router ID (the router ID is a 32-bit unique identifier which,
while not guaranteed, tends to be an IPv4 address unique to the device).
Otherwise we fall back to the previous method of finding the root_ip.
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