Changes to allow Kafka set-up to be able to use existing Hadoop ZooKeeper quorum
Changes to remove instance variable from library function znode_exists? and also to handle any ZK connection failure gracefully
Created a Kafka specific attribute file to overwrite the attributes in Kafka community cookbook
Changed Kafka server port to 6667
Merge pull request #337 from bijugs/fix_req_316

Changes to allow Kafka set-up to be able to use existing Hadoop Zookeeper quorum