SPARK-2427: Fix Scala examples that use the wrong command line arguments index

The Scala examples HBaseTest and HdfsTest don't use the correct indexes for the command line arguments. This due to to the fix of JIRA 1565, where these examples were not correctly adapted to the new usage of the submit script.

Author: Artjom-Metro <Artjom-Metro@users.noreply.github.com>
Author: Artjom-Metro <artjom31415@googlemail.com>

Closes #1353 from Artjom-Metro/fix_examples and squashes the following commits:

6111801 [Artjom-Metro] Reduce the default number of iterations
cfaa73c [Artjom-Metro] Fix some examples that use the wrong index to access the command line arguments