fix os_arch computation

[jpiron]

trafficstars

Ternary filter requires parenthesis around the test. SEE: https://docs.ansible.com/ansible/latest/user_guide/playbooks_filters.html#defining-different-values-for-true-false-null-ternary

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[cla-checker-service[bot]]

💚 CLA has been signed