Refactor BM deployment to use '--work-dir'

We added '--output-dir' just a few weeks ago, now it seems
we want to use '--work-dir'. See:
https://review.opendev.org/775302.

Let's re-factor to use the common consistent working directory.

Depends-On: https://review.opendev.org/780968
Change-Id: Ic903c6d1769d6a6a026208b9857680a115de6c31

tripleo_ansible/playbooks/cli-overcloud-node-provision.yaml

@@ -176,17 +176,10 @@
         content: "{{ network_ports_environment.environment | default({}) | to_nice_yaml(indent=2) }}"
       when: manage_network_ports|default(false)
 
-    - name: Ensure inventory working directory exists
-      file:
-        path: "{{ output_dir }}/{{ stack_name }}"
-        state: directory
-      when:
-        - manage_network_ports|default(false)
-
     - name: Generate ansible inventory
       tripleo_generate_ansible_inventory:
         plan: "{{ stack_name }}"
-        work_dir: "{{ output_dir }}/{{ stack_name }}"
+        work_dir: "{{ working_dir }}"
         ssh_network: "{{ ssh_network }}"
         ansible_ssh_user: "{{ ssh_user_name }}"
         ansible_python_interpreter: "{{ python_interpreter }}"