Sort AMIs in the opposite order to correctly choose one

Previously, we iterated through the list of possible AMIs and kept track
of the oldest non-fork AMI to use for provisioning. Instead, we should
have been finding the newest non-fork AMI. By iterating in the other
direction, we can achieve that.

Signed-off-by: Steve Kuznetsov <skuznets@redhat.com>

oct/ansible/oct/roles/aws-up/tasks/main.yml

@@ -44,7 +44,7 @@
       image_stage: '{{ origin_ci_aws_ami_stage }}'
       ready: 'yes'
     sort: 'creationDate'
-    sort_order: descending
+    sort_order: ascending
     no_result_action: fail
   register: ami_facts