Fix Java example in Streaming Programming Guide

"val conf" was used instead of "SparkConf conf" in Java snippet.

Author: Santiago M. Mola <santi@mola.io>

Closes #2472 from smola/patch-1 and squashes the following commits:

5bfeb9b [Santiago M. Mola] Fix Java example in Streaming Programming Guide
[PySpark] remove unnecessary use of numSlices from pyspark tests

Author: Matthew Farrellee <matt@redhat.com>

Closes #2467 from mattf/master-pyspark-remove-numslices-from-tests and squashes the following commits:

c49a87b [Matthew Farrellee] [PySpark] remove unnecessary use of numSlices from pyspark tests