[core] V1JobsServlet should log HDFS related error when trying to save workflow definition

If V1JobsServlet DEBUG level logging is turned on and tryCreateOnDFS catches an exception and tried to log the details, only the following is printed to the log:

Could not write XML [%s] to HDFS. Error message: %s

Instead of %s we should use {0} and {1} to get a meaningful error message. Or we should use String.format