Make nova and nova-kvm elements more compatible.

Create the nova /mnt/state/var/lib/nova directory at
configuration time instead of during post-configure.

This fixes a permission issue which can occur when using
nova with nova-kvm in that /mnt/state/var/lib/nova
was ending up with root:root perms because
nova-kvm/os-refresh-config/configure.d/80-nova-kvm
ran first.

Change-Id: Ifba6af6b55ab21c03f909a8846e7751abca9781e
Closes-bug: 1271691
Merge "Make nova and nova-kvm elements more compatible."