Filter out Cinder VG from LVM scan

Without filtering out the cinder-volumes VG, LVM will happily scan and import VGs defined on any block devices within /dev. This can be annoying and problematic because any LV/VGs created on Cinder block devices are then visible on the host as well.

This commit adds a filter rule in /etc/lvm/lvm.conf which rejects devices which match `node['cinder']['storage']['lvm']['volume_group']`.

Fixes DE253