Rename hieradata_files result var
Rename hieradata_files result var

This var is used internally in tripleo-ansible tripleo_hieradata role so
the check result is overwriting the variable used to generate hiera.yaml

Closes-Bug: #1933850
Change-Id: I9b6cdad78f834c097226bd1681fa2e13791c33aa

openstack/tripleo-common,openstack/tripleo-common