Updated openstack/openstack
Project: openstack/sahara  4170900df0ad3511d3a82142554ab57cfab1b183

Documentation for the Spark plugin

This patch adds a documentation page for the the Spark plugin, using the
Vanilla plugin page as a template.

Change-Id: Ic6a06e7cfd1b2e0a9ad5dbd1f93b29158be19aa2