Add the bare of cdh5_base role. This does not include actual configuration.
We should install wget at first
* Add jdk role
* Install jdk at first of cdh5 playbook
Add check of state of SELinux to avoid fail when SELinux is disabled
* Add roles and playbooks to construct HDFS environment
* Add playbooks to operate HDFS
Change user in initializing /user directory on HDFS
Change to use default yarn.app.mapreduce.am.staging-dir
Change to configure mode of /user/history on HDFS,
when we initialize HDFS.
Remove unnecessary parameter yarn.app.mapreduce.am.staging-dir from yarn-site.xml