Only do etckeeper commit when there are uncomitted changes

roles/cleanup/tasks/main.yml

@@ -1,6 +1,12 @@
 ---
 
+-   name: check for uncommitted changes
+    command: 'etckeeper unclean'
+    register: etckeeper_unclean
+    failed_when: false
+
 -   name: etckeeper commit
     command: "{{ item }}"
     with_items:
         - 'etckeeper commit "Ansible (re-)build playbook run"'
+    when: etckeeper_unclean.rc == 0