Remove containers' list file.

Remove containers-list file (saved during a resource creation
stage), before running a Tobiko second stage, if we expect changes
to the containers list (For example, after the FFU upgrade procedure).

Change-Id: I65c7b61ab1c472b2eb68530ca8246297cb1c14bc

infrared_plugin/plugin.spec

@@ -268,6 +268,14 @@ subparsers:
                 Timeout error is raised if an ubuntu instance is not reachable
                 before it expires
             ansible_variable: ubuntu_is_reachable_timeout
+          cleanup-containerlist-file:
+            type: Bool
+            help:  |
+                 Remove containers-list file (saved during a resource creation
+                 stage) before running a Tobiko second stage, if we expect changes
+                 to the containers list (For example, after the FFU upgrade).
+            default: False
+            ansible_variable: cleanup_containerlist_file
 
 
       - title: Cleanup stage

infrared_plugin/roles/tobiko-ir-before-run/tasks/main.yaml

@@ -66,3 +66,18 @@
     - groups.get("undercloud")
     - test_host is defined
     - test_host not in groups.undercloud
+
+- name: Remove the containers list file, if required
+  block:
+    - name: Save the containers list file, if exists
+      copy:
+        dest: ~/expected_containers_list_df.old.csv
+        src: ~/expected_containers_list_df.csv
+        remote_src: yes
+      failed_when: false
+
+    - name: Remove the original containers list file
+      file:
+        path: ~/expected_containers_list_df.csv
+        state: absent
+  when: cleanup_containerlist_file | bool