scale: fixes for compute scale down

- Force fact gathering so that we're ensured to have the proper FQDN
- Update start squence so that our scale down process is not starting
  from irrelevant steps
- correct list evaluation. The compute service argument should have one
  item in the list. Prior to this change it was expecting zero items,
  which was causing the removal tasks to skip.

Co-Authored-By: "Cedric Jeanneret (Tengu) <cjeanner@redhat.com>"
Co-Authored-By: "Emilien Macchi <emilien@redhat.com>"
Co-Authored-By: "Kevin Carter (cloudnull) <kecarter@redhat.com>"

Change-Id: I7c1615685718924e872a2f9173b15c63bba8c482
Closes-Bug: #1856062

common/deploy-steps.j2

@@ -1494,7 +1494,11 @@ outputs:
                 - facts
             - hosts: DEPLOY_TARGET_HOST
               name: Scaling
-              gather_facts: {{ '"{{' }} gather_facts | default(false) {{ '}}"' }}
+              # NOTE(cloudnull): This is set to true explicitly so that we have up-to-date facts
+              #                  on all DEPLOY_TARGET_HOST when performing a scaling operation.
+              #                  Without up-to-date facts, we're creating a potential failure
+              #                  scenario.
+              gather_facts: true
               any_errors_fatal: yes
               become: false
               vars:
@@ -1513,7 +1517,7 @@ outputs:
                 # If a task is allowed to fail, it needs to be configured at
                 # the task definition level but not here.
                 - include_tasks: scale_steps_tasks.yaml
-                  with_sequence: start=0 end={{scale_steps_max}}
+                  with_sequence: start=1 end={{scale_steps_max}}
                   loop_control:
                     loop_var: step
                   tags: always

deployment/nova/nova-compute-container-puppet.yaml

@@ -1024,7 +1024,7 @@ outputs:
               delegate_to: localhost
               check_mode: no
               when:
-                - (nova_compute_service | length) < 1
+                - (nova_compute_service | length) <= 1
             - name: Stop nova-compute healthcheck container
               service:
                 name: tripleo_nova_compute_healthcheck
@@ -1042,7 +1042,7 @@ outputs:
               delegate_to: localhost
               check_mode: no
               when:
-                - (nova_compute_service | length) < 1
+                - (nova_compute_service | length) <= 1
       fast_forward_upgrade_tasks:
         - when:
             - step|int == 0