This patch removes the warning:
TASK [openstack_hosts : Install distro packages] *******************************
[WARNING]: when statements should not include jinja2 templating delimiters
such as {{ }} or {% %}. Found: {{ openstack_host_distro_packages | length > 0
}}
changed: [localhost]
Change-Id: Ifc598a2a4ce8f830dd1e10e6b0c2bbdcb4ae5447