Also simplify the code and improve logging in general.
The previous code did this: search for the ID in the address map. If it
couldn't be found, perform a read barrier and search again. If it again
couldn't be found, return.
This algorithm depended on the fact that IP addresses were stored in
group 0 configuration. The read barrier was used to obtain the most
recent configuration, and if the IP was not a part of address map after
the read barrier, that meant it's simply not a member of group 0.
This logic no longer applies so we can simplify the code.
Furthermore, when I was fixing the replace operation with Raft enabled,
at some point I had a "working" solution with all tests passing. But I
was suspicious and checked if the replaced node got removed from
group 0. It wasn't. So the replace finished "successfully", but we had
an additional (voting!) member of group 0 which didn't correspond to
a token ring member.
The last version of my fixes ensure that the node gets removed by the
replacing node. But the system is fragile and nothing prevents us from
breaking this again. At least log an error for now. Regression tests
will be added later.
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