Log upload script improvements

* Ignore log files older than 'days', otherwise they will be uploaded (given that HDFS paths older than this won't be checked).
* Track skipped and failed uploads.
* Search for "job" in log file name to make more flexible, given that there apparently isn't consistency with log file names.  Don't assume log file name starts with "job".
* Check whether the job conf xml file is found and skip upload if it's not.  Also fixes issue with this var being undefined and used later.
* Added better logging to track issues.