Temporarily disable certificate check on get_url for slave image build

14:04:03 TASK [slave_tools : get_url] ***************************************************
14:06:14 fatal: [slavecommon]: FAILED! => {"changed": false, "failed": true, "msg": "Failed to validate the SSL certificate for qa.nuxeo.org:443. Make sure your managed systems have a valid CA certificate installed. You can use validate_certs=False if you do not need to confirm the servers identity but this is unsafe and not recommended. Paths checked for this platform: /etc/ssl/certs, /etc/pki/ca-trust/extracted/pem, /etc/pki/tls/certs, /usr/share/ca-certificates/cacert.org, /etc/ansible"}