See bug 1034384, bug 1037590.
This reverts commit https://github.com/openstack/nova/commit/391f345d,
but leaves the DB migration in place while adding a further
migration to reverse it.
The motivation for reversion is that the per-user quota logic would
totally undermine the per-project quotas set for a pre-existing
openstack install.
The per-user quota logic could be re-introduced in a fixed state
after Folsom-3.
Change-Id: Idd4b55a2404a25f43f6737b661f828c28501066f
1cf475d7a1