---
- name: check whether {{apk}}.apk.bak exists
  shell: cd {{root_dir}} && [ -f {{apk}}.apk.bak ]
  ignore_errors: true
  register: result
- name: revert {{apk}}.apk.bak
  when: result is succeeded
  shell: cd {{root_dir}} && rm -f {{apk}}.apk && mv {{apk}}.apk.bak {{apk}}.apk