Role breaks the run when should be skipped by condition

[aleksandr-vin]

This playbook will fail even if it should skip the whole run:

- hosts: all
  roles:
  - role: letsencrypt
    when: false

Checked on 38fa972.

This is the output:

ansible-playbook -i hosts --diff -b xxx.yml --limit monitor-01.test

PLAY [all] *********************************************************************

TASK [setup] *******************************************************************
ok: [monitor-01.test]

TASK [letsencrypt : apt] *******************************************************
skipping: [monitor-01.test]

TASK [letsencrypt : include_vars] **********************************************
skipping: [monitor-01.test] => (item=/private/etc/ansible/roles/letsencrypt/vars/../vars/default.yml)

TASK [letsencrypt : Install depends] *******************************************
fatal: [monitor-01.test]: FAILED! => {"failed": true, "msg": "'letsencrypt_depends' is undefined"}
    to retry, use: --limit @/tmp/xxx.retry

PLAY RECAP *********************************************************************
monitor-01.test            : ok=1    changed=0    unreachable=0    failed=1