Finish compacting pre-Icehouse database migrations

Compacts the pre-Icehouse database migrations into a
single migration (216_havana.py).

Pre-Icehouse users will now need to upgrade to Havana before
running any Icehouse migrations.

Tested on MySQL and PostgreSQL schemas on Fedora 19 to ensure the
new compacted migration generates an identical schema to the
previous migrate scripts in Havana.

Specific changes include:

  1) Add aggregate metadata unique constraint.

  2) Fix migrations index (add deleted column).

  3) Add pci_devices table.

  4) fix migrations_instance_uuid_and_status_idx index.

Implements: blueprint compact-havana-db-migrations

Change-Id: Id96e13b0ed65837761bd173c9e32ebcc1ff5f376
Merge "Finish compacting pre-Icehouse database migrations"