Changed use of Jinja filters as tests

[LindsayHill]

The use of when mistral_install_latest|changed is now deprecated.

This should be when mistral_install_latest is changed

Looks like this will require a minimum Ansible version of 2.5, but this is also the oldest version supported by upstream. We should plan to change our minimum Ansible version to 2.5.

[arm4b]

👍

[arm4b]

Using Ansible-provided jinja tests as filters will be removed in Ansible 2.9.

Hm, I think it's too early for us to include change like this and worth waiting a little bit more.

In #210 we just bumped min Ansible version to v2.3 which is OK, but setting up minimum v2.5 is too much.
Needs more time.

[arm4b]

Nevermind, I was looking at the wrong Ansible support table.
The correct one is: https://docs.ansible.com/ansible/devel/reference_appendices/release_and_maintenance.html

Good with bumping min Ansible to v2.5 👍

[LindsayHill]

Yeah - it was a little bit of a surprise to me to realize that 2.5 was the oldest supported version.

[cognifloyd]

Using "is" instead of "|" is supported in ansible versions older than 2.4 as that is a Jinja feature. It was ansible that also made the tests available as filters. Using the tests as filters is deprecated, but using them as actual Jinja tests has worked for a long time, possibly since introduced.

I will carve out a moment this weekend to bump the min version to 2.5 and clean up the deprecated notices in #190. :)

[arm4b]

I've tested this change with older version and @cognifloyd is right about Ansible/Jinja filters vs tests, it works OK with Ansible before v2.5.0