fix error with old hadoop-client libraries

With hadoop-client version 2.0.2-alpha the following error occur when using with the latest Hadoop version:

Exception in thread "main" java.util.ServiceConfigurationError: org.apache.hadoop.fs.FileSystem: Provider org.apache.hadoop.hdfs.Hft
pFileSystem could not be instantiated: java.lang.IllegalAccessError: tried to access method org.apache.hadoop.fs.DelegationTokenRene
wer.<init>(Ljava/lang/Class;)V from class org.apache.hadoop.hdfs.HftpFileSystem (...)

Fixed by upgrading to 2.2.0