fix: correct config option `preferred_dcs` in poppy.conf
fix: correct config option `preferred_dcs` in poppy.conf

Change-Id: I632872955af909075881ec0ee4689ee7c9e6c3fb

obulpathi/poppy,stackforge/poppy,obulpathi/poppy,obulpathi/poppy,stackforge/poppy,openstack/poppy,openstack/poppy,openstack/poppy,stackforge/poppy