BackupServerUtil.getWALFilesOlderThan() should handle oldWALs properly

I was running TestBackupDescribe where I saw the following being passed to BackupServerUtil.getWALFilesOlderThan():

hdfs://localhost:59278/user/tyu/test-data/a42ac21a-2097-49d8-9c0e-86991e104e4e/oldWALs/hregion-05273083.default.1465333387177

Since the filename doesn't represent a server, the following call throws exception:

ServerName.parsePort(String) line: 150
BackupClientUtil.parseHostFromOldLog(Path) line: 136