SPARK-938 - Openstack Swift object storage support

This is initial documentation describing how to integrate Spark with
Swift. This commit contains documentation for stand alone cluster.
Next patches will contain details how to integrate Swift in other
deployment of Spark.

docs/openstack-integration.md

@@ -60,7 +60,7 @@ Create core-sites.xml and place it under /spark/conf directory. Configure core-s
 	      <value>true</value>
 	  </property>
 
-We left with `fs.swift.service.<PROVIDER>.tenant`, `fs.swift.service.<PROVIDER>.username`, `fs.swift.service.<PROVIDER>.password`. The best way is to provide them to SparkContext in run time, which seems to be impossible yet.
+We left with `fs.swift.service.<PROVIDER>.tenant`, `fs.swift.service.<PROVIDER>.username`, `fs.swift.service.<PROVIDER>.password`. The best way to provide those parameters to SparkContext in run time, which seems to be impossible yet.
 Another approach is to change Hadoop Swift FS driver to provide them via system environment variables. For now we provide them via core-sites.xml 
 
 	   <property>