Pin to posgresql 2.5 module

- Later version breaks backward compatibility
- Sort fixtures for better maintainability

Change-Id: I4197041025f5d89a02c83bfee20ef2f2788f756f
(cherry picked from commit 0ee4be96653b3d88bd2fea33e24453744d96f11a)
Prepping module for 2.2.0 release.

Updated Modulefile to version 2.2.0. Updated README.md with
latest release notes.

Change-Id: I9aab1c3ff9b5f801dd496c4947cba81fe4f879ac
(cherry picked from commit 4100e958fdecebe6eb486c8a09ba6954bcae5d71)