checking if ssl is enabled before trying to load auth client properties

just added a line to check if SSL is enabled before loading auth client properties. 
For file-tailer, when you install, it places an authClientProperties file in the same place as the other properties file, and sets that as the default authClientPropertiesPath. That would be a good idea here too, right?
https://github.com/caskdata/cdap-ingest/blob/31f19a16287d6e427ab30f742b9cd08b5d24b890/cdap-file-tailer/src/main/java/co/cask/cdap/filetailer/config/PipeConfigurationImpl.java#L216