Fix syntax for set_fact ansible task.
Fix syntax for set_fact ansible task.

Error in ansible task causes upgrade job to fail:
tripleo-ci-centos-7-scenario000-multinode-oooq-container-upgrades

Closes-Bug: 1778455

Change-Id: I4040c7cc004e8ee81355bbae6ccc1a0a4dfd0822

dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates