Remove redundant vars line
Remove redundant vars line

This line snuck in with If97b59759d8f89af371f8b0a4538402b1c3320c1
probably to bring it in line with other OSA roles, but should already
be covered by the distribution_major_version line above.

Change-Id: I6d48bf93be68d4fe89c9922c9b53beb6cea7ced5

openstack/openstack-ansible-openstack_hosts,openstack/openstack-ansible-openstack_hosts