standardize release note page ordering
standardize release note page ordering

In order to support automatically updating the release notes when we
create stable branches, we want the pages to be in a standard order.
This patch updates the order to be reverse chronological, so the most
recent notes appear at the top.

Change-Id: Ib364dcc8eb31275a31c83b68d7914263b183e393
Signed-off-by: Doug Hellmann <0798ebecfb7bc4dfb9d0445c2fa030eb64e1fa1c@doughellmann.com>

hanlind/nova,mahak/nova,mikalstill/nova,alaski/nova,phenoxim/nova,klmitch/nova,klmitch/nova,klmitch/nova,alaski/nova,rahulunair/nova,vmturbo/nova,sebrandon1/nova,openstack/nova,vmturbo/nova,cloudbase/nova,jianghuaw/nova,phenoxim/nova,mahak/nova,mikalstill/nova,rajalokan/nova,rahulunair/nova,rajalokan/nova,Juniper/nova,vmturbo/nova,gooddata/openstack-nova,vmturbo/nova,hanlind/nova,hanlind/nova,sebrandon1/nova,gooddata/openstack-nova,sebrandon1/nova,rajalokan/nova,jianghuaw/nova,openstack/nova,cloudbase/nova,klmitch/nova,rahulunair/nova,cloudbase/nova,jianghuaw/nova,mahak/nova,rajalokan/nova,openstack/nova,gooddata/openstack-nova,Juniper/nova,jianghuaw/nova,Juniper/nova,mikalstill/nova,Juniper/nova,gooddata/openstack-nova