Add ratelimiting options to nova::api

nova master now has proper support for ratelimitng via the api-paste.ini
This commit adds a configuration option based on
https://github.com/openstack/nova/commit/08d6932963c9cbbd605833933bf5ea0f66127dc4

Change-Id: Ic29d4aa15fdf8b4613a1c3a641c60e6d8377f418
Pin to posgresql 2.5 module

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

Change-Id: I30ac98687b4f6cedf241746f32d7d57678e6adbb
fix stackforge web link

Change-Id: Ibf88b2796706d27e3e420eed18a69a5189041bac