Spark on Yarn should use yarn approved directories for spark.local.dir and tmp

Spark on Yarn should use the directories that yarn allocates for the application rather then the user specified ones in spark.local.dir or /tmp.  This way Yarn can manage and cleanup the directories as needed and the user won't have to know how the yarn cluster is configured.

I also noticed the docs referred to the old and removed config --user so I removed that while I was updating.