Correct error in README
Correct error in README

Cluster name node configuration should be `node.default[:cassandra][:config][:cluster_name]`
vkhatri/cassandra-chef-cookbook,vdemonchy/cassandra-chef-cookbook,vkhatri/cassandra-chef-cookbook,vdemonchy/cassandra-chef-cookbook,vdemonchy/cassandra-chef-cookbook,criteo-forks/cassandra-chef-cookbook,michaelklishin/cassandra-chef-cookbook,vkhatri/cassandra-chef-cookbook,michaelklishin/cassandra-chef-cookbook,criteo-forks/cassandra-chef-cookbook,criteo-forks/cassandra-chef-cookbook,michaelklishin/cassandra-chef-cookbook