This moves the hiera root under /opt/system-config so it can reach
into both private and public hiera directories. This implies that
hiera data will live in a hiera/ directory in system-config.
Manual: This requires a manual change to the puppetmaster system. A
rooter must move /etc/puppet/hieradata to /opt/system-config/hieradata
Spec: http://specs.openstack.org/openstack-infra/infra-specs/specs/public_hiera.html
Change-Id: I1736759ee9ac7cd0c206538ed0a2f6d0d71ea440