Compact pre-Icehouse database migrations <= 150.

Compacts the pre-Icehouse database migrations <= 150 into a
single migration (150_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) Make migrations.instance_uuid a String 36.

 2) Add migrations_instance_uuid_and_status_idx index.

 3) rename instance info caches seq (postgresql only, dropped from
    baseline)

 4) Add source_node, dest_node columns to migrations. Indexes...

 5) Add new volume usage cache table.

 6) Drop aggregates.availability_zone column.

 7) Drop services.availability_zone column.

 8) Add instance actions tables.

 9) Convert PostgreSQL to INET.

 10) Add host to instance faults.

Implements: blueprint compact-havana-db-migrations

Change-Id: Ic0c318967b69af32536b5ab6999affc7755ec442
Merge "Compact pre-Icehouse database migrations <= 150."