Updated openstack/openstack
Project: openstack/sahara  e481a48ef08252cd931c71369592c87c0e39c704

Add CDH plugin documents

We added documents on how to deploy and enable CDH plugin in Sahara,
and how to build images for CDH plugin. We also modified some other
pages to add involved contents and links.

Closes-Bug: #1395583

Change-Id: If1451eaf4a570165a87313dab347422480546f0c