We need to pass host through from SaslAuthProvider, to SaslAuthenticator, so that it can be used with different hosts dynamically.
https://github.com/datastax/python-driver/blob/25a09dc88d3d2df50250250e7810e870d02c4aa7/cassandra/auth.py#L157-L171
Uncovered by Philip Doctor while integrating into OpsCenter
https://github.com/datastax/python-driver/pull/302
+1 changes look good.