Add the option of specifying a custom overcloud stack name

This change adds the option to specify the overcloud stack name
when doing the update/upgrade.

Change-Id: I82cead877f3998bbbd695cd16f1aacb1c6cd9a9a
(cherry picked from commit 84419c40f2)

infrared_plugin/main.yml

@@ -118,5 +118,9 @@
          upgrade_hci: true
       when: install.upgrade.hci
 
+    - name: Set overcloud credentials file
+      set_fact:
+         overcloud_rc: "{{ working_dir }}/{{ install.overcloud.stack }}rc"
+
   roles:
     - tripleo-upgrade

infrared_plugin/plugin.spec

@@ -120,3 +120,9 @@ subparsers:
                       help: |
                           Directory containing the templates of the overcloud deployment.
                       default: virt
+            - title: TripleO Options
+              options:
+                  overcloud-stack:
+                      type: Value
+                      help: Overcloud stack name
+                      default: "overcloud"