Removed the db recipe

The db recipe have been removed. It is up to the operator to
setup the database, users, and grants before deploying openstack.
It has been moved to the `openstack-db` recipe in the
`openstack-ops-database` wrapper cookbook.  Needed to converge
in the register tests, so Chef loads the provider and creates
the classes.  The db spec was previously doing that, which allowed
tests to pass.

Change-Id: I301b7fc625790960efd99d08395b91204ae18107
Removed the use of non-standard ohai plugin

We now have a helper method `#address_for` to return the
IP of a given interface. Switched out the ohai use
in favor of `#address_for`.  Also, updated berkshelf
to 2.x which handles dep resolution correctly.  I run
into problems getting berkshelf to lock to the new 0.3.0
openstack-common w/o updating berkshelf.

Change-Id: If5988dc5290ed8d5faa3950c1995f9943d9efe65
Ability to ignore db migrations

There are cases where migrations should not be executed. For example when
upgrading a zone, and the identity database is replicated across many zones.
Having the ability to toggle migration execution is useful (and a use-case
we have :))

Change-Id: I9d820e853d8afa13a55dbd49e5335d34246d97ba
Merge "Ability to ignore db migrations"
Merge "Removed the db recipe"