Remove Vault public/private keys after testing.

Public and private key files were created but not removed when testing
the Vault module. This was fixed by adding a task to remove them to
Vault's env_cleanup playbook.

tests/vault/env_cleanup.yml

@@ -62,3 +62,11 @@
     file:
       path: "{{ ansible_env.HOME }}/in.txt"
       state: absent
+
+  - name: Remove private/public key files.
+    shell:
+      cmd: rm -f private.pem public.pem
+    delegate_to: localhost
+    become: no
+    args:
+      warn: no  # suppres warning for not using the `file` module.

tests/vault/env_setup.yml

-# Tasks executed to ensure a sane environment to test IPA Vault module.
+---
+  # Tasks executed to ensure a sane environment to test IPA Vault module.
+  - name: Ensure environment is clean.
+    import_tasks: env_cleanup.yml
 
   - name: Create private key file.
     shell:
@@ -12,9 +15,6 @@
     delegate_to: localhost
     become: no
 
-  - name: Ensure environment is clean.
-    import_tasks: env_cleanup.yml
-
   - name: Copy password file to target host.
     copy:
       src: "{{ playbook_dir }}/password.txt"