Ensure correct tftp directory ownership for Ironic

Ironic is currently unable to create tftp files due to tftp directory
being owned by the root user. Ironic is also unable to cache images
due to root ownership. This patch corrects both issues by setting the
proper ownership and moves /var/lib/ironic to /mnt/state/

Change-Id: Ia24b09cab88359de56ce4fa662f5f301835b91dd
Merge "Ensure correct tftp directory ownership for Ironic"