[SPARK-5970][core] Register directory created in getOrCreateLocalRootDirs for automatic deletion.

As documented in createDirectory, the result of createDirectory is not registered for automatic removal. Currently there are 4 directories left in `/tmp` after just running `pyspark`.

Author: Milan Straka <fox@ucw.cz>

Closes #4759 from foxik/remove-tmp-dirs and squashes the following commits:

280450d [Milan Straka] Use createTempDir in getOrCreateLocalRootDirs...