Changes to allow users to skip the datanode restart coordination logic

Changes in this pull request
- will allow users to skip the HDFS datanode restart coordination process so that the cluster can be bounced quickly and also will allow users to use the recipe in environments where ZooKeeper is not required.
- will skip the restart of datanode process if the process was started (manually or otherwise) after the previous restart failure through chef client run. 

Refer req #349 .