HAServiceUtil should not directly use HDFS.

HAServiceUtil is tightly coupled with HDFS Filesystem. We have a plan to implement multiple HA implementations like HDFS and Zookeeper. We need to abstract it to support multiple implementations.

Also, it forces TajoClient to have Hadoop HDFS dependency. If we decouple using HDFS from HAServiceUtil, we can eliminate HDFS dependency from TajoClient.