Fix rabbitmq prechecks broken due to Ansible upgrade
Fix rabbitmq prechecks broken due to Ansible upgrade

In Ansible 2.3.0 when statements should not include jinja2 templating
delimiters such as {{ }} or {% %}, and gate is broken with Ansible 2.3.1.

This patchset rewrite when statement in rabbitmq precheck task to not use
string interpolation.

Change-Id: Ie2f1666cc8ced7cf20ceba40c7c7aaec750778f9
Closes-Bug: #1695111

dardelean/kolla-ansible,dardelean/kolla-ansible,dardelean/kolla-ansible