Load the variables from an architecture specific file first --
ansible's ansible_architecture fact for arm64 is aarch64 (it's all
confusing, Ubuntu calls it arm64). Add this file that sets up the
repo as "ubuntu-ports", which is our mirror of ports.ubuntu.com
Change-Id: Ieb50ae29c7f822e831ef1e32fdd03f74a93e298a
44bc52a539