Charm fails to install on Focal due to deprecated functionality is Ansible v2.9

[Jose Guedez]

The charm fails to install on focal. The charm relies on Ansible for the heavy lifting, and uses deprecated filters (https://docs.ansible.com/ansible/latest/porting_guides/porting_guide_2.5.html#jinja-tests-used-as-filters). These filters need to be migrated to use the newer "test" syntax (https://docs.ansible.com/ansible/latest/user_guide/playbooks_tests.html#task-results).

"result | success" becomes "result is successful"

At least one instance of this in https://git.launchpad.net/charm-elasticsearch/tree/tasks/setup-ufw.yml#n52

Ansible log with error details:
2020-02-11 01:58:51 DEBUG install fatal: [localhost]: FAILED! => {"msg": "The conditional check 'firewall_enabled and cluster_health|success and cluster_health.json.number_of_nodes > 1' failed. The error was: template error while templating string: no filter named 'success'. String: {% if firewall_enabled and cluster_health|success and cluster_health.json.number_of_nodes > 1 %} True {% else %} False {% endif %}\n\nThe error appears to be in '/var/lib/juju/agents/unit-elasticsearch-0/charm/tasks/setup-ufw.yml': line 50, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n- name: Deny all incoming requests on 9300 once unit is part of cluster\n ^ here\n"}

[Tom Haddon (mthaddon)]

Also, charm-helpers will need updating to 0.20.9 or greater per https://github.com/juju/charm-helpers/pull/423