Remove unused nodepool_file_nodepool_elements_* variables
Remove unused nodepool_file_nodepool_elements_* variables

These are left over from a time where we did sync nodepool elements
directory.

Change-Id: Ic7c4313424f9115f4f0587d47b64210a1baca70a
Signed-off-by: Paul Belanger <e7139c8e6c4ea75cc1c287ce081b2dc0f3ab39ec@redhat.com>

openstack/ansible-role-nodepool,openstack/ansible-role-nodepool