When adding new nodes to a cluster which has authentication enabled, we end up losing cassandra user's current crendentials and they get reverted back to default cassandra/cassandra credentials

Made the following observation:

When adding new nodes to an existing C* cluster with authentication enabled we end up loosing password information about `cassandra` user.

Initial Setup

• Create a 5 node cluster with system_auth having RF=5 and NetworkTopologyStrategy
• Enable PasswordAuthenticator on this cluster and update the password for 'cassandra' user to say 'password' via the alter query
• Make sure you run nodetool repair on all the nodes

Test case

• Now go ahead and add 5 more nodes to this cluster.
• Run nodetool repair on all the 10 nodes now
• Decommission the original 5 nodes such that only the new 5 nodes are in the cluster now

• Run cqlsh and try to connect to this cluster using old user name and password, cassandra/password

I was unable to connect to the nodes with the original credentials and was only able to connect using the default cassandra/cassandra credentials

From the conversation over IIRC

`beobal: sood: that definitely shouldn't happen. The new nodes should only create the default superuser role if there are 0 roles currently defined (including that default one)`