Update developer docs for new rolling upgrade repos
Update developer docs for new rolling upgrade repos

Closes-Bug:  #1615698
Change-Id: I5a5fecd46901c9b8eae9ac548f115f17acf090de

openstack/keystone,ilay09/keystone,rajalokan/keystone,mahak/keystone,mahak/keystone,rajalokan/keystone,mahak/keystone,rajalokan/keystone,ilay09/keystone,ilay09/keystone,openstack/keystone,openstack/keystone