Support for HDFS HA

I have run into issues when using Slurper on a cluster with NameNode HA enabled. 

The current approach tries to resolve the fragment of fs.defaultFS to the hostname (via InetAddress.getByName.getCanonicalHostName), but in case of NameNode HA, the current nameservice is set there that doesn't correspond to any hostname. In consequence, "java.net.UnknownHostException" is thrown.