minor cleanup of variable names after PR feedback
minor cleanup of variable names after PR feedback

jut-io/node-cassandra-native-driver,simong/node-cassandra-native-driver,jut-io/node-cassandra-native-driver,jut-io/node-cassandra-native-driver,simong/node-cassandra-native-driver,simong/node-cassandra-native-driver,simong/node-cassandra-native-driver,jut-io/node-cassandra-native-driver