Addition of Coraid block storage driver information

Added new section to config reference manual showing Coraid driver
installation and configuration information

Added edits to files per OpenStack review
Adding additional edits per review

Closes-Bug: #1235397

Change-Id: I966b8e2fc63bbada610ed8b2fcfad8164fffb4b0
Implements: coraid-driver.xml
Modifies: section_volume-drivers.xml
Merge "Addition of Coraid block storage driver information"