Adding the list for OpenStack discussions in Vietnamese

Change-Id: If7c4fe521bd17ea16e5fa1528c6cff19898f458e
Reviewed-on: https://review.openstack.org/30368
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins