Fix peers v2 system table behaviour when 2 nodes swap their IP Addresses

Throw if node id has been changed and does not match directory. If, however the _ip_ address has changed, issue Startup and correct the IP address. Disallow picking over identity of other nodes via hijacking their IPs or via overriding local node id with theirs.

Patch by Alex Petrov; reviewed by Sam Tunnicliffe for CASSANDRA-19221
4 files changed