Use true/false instead of yes/no

roles/openshift_cloud_provider/defaults/main.yml

@@ -4,4 +4,4 @@ openshift_gcp_prefix: ''
 openshift_gcp_network_name: "{{ openshift_gcp_prefix }}network"
 openshift_gcp_multizone: False
 openshift_openstack_ca_file_path: '/etc/origin/cloudprovider/openstack.crt'
-openshift_cloudprovider_openstack_blockstorage_ignore_volume_az: "no"
+openshift_cloudprovider_openstack_blockstorage_ignore_volume_az: false

roles/openshift_cloud_provider/templates/openstack.conf.j2

@@ -23,7 +23,7 @@ ca-file = {{ openshift_openstack_ca_file_path }}
 subnet-id = {{ openshift_cloudprovider_openstack_lb_subnet_id }}
 {% endif %}
 [BlockStorage]
-ignore-volume-az = {{ openshift_cloudprovider_openstack_blockstorage_ignore_volume_az }}
+ignore-volume-az = {{ openshift_cloudprovider_openstack_blockstorage_ignore_volume_az | ternary('yes', 'no') }}
 {% if openshift_cloudprovider_openstack_blockstorage_version is defined %}
 bs-version={{ openshift_cloudprovider_openstack_blockstorage_version }}
 {% endif %}