Improve tempest-cleanup ansible role

The patch implements a new flag which will fail a job when any
resources were leaked - that can be used for verification that
tests are cleaning their resources after they are finished.

Change-Id: I212cdce9713c80491153b0bbdb313e75c1f96f1d
diff --git a/roles/tempest-cleanup/tasks/dry_run.yaml b/roles/tempest-cleanup/tasks/dry_run.yaml
new file mode 100644
index 0000000..46749ab
--- /dev/null
+++ b/roles/tempest-cleanup/tasks/dry_run.yaml
@@ -0,0 +1,7 @@
+---
+- name: Run tempest cleanup dry-run
+  become: yes
+  become_user: tempest
+  command: tox -evenv-tempest -- tempest cleanup --dry-run --debug
+  args:
+    chdir: "{{ devstack_base_dir }}/tempest"