Updated openstack/openstack
Project: openstack/heat  957fd8ecd0849ca155e868731c8f1acb6deddbf2

Alter models and add migration

We must have correct models i.e. models that correspond
database schema to use sqlalchemy features.
Update models.py and add migration script to correct
database schema and get rid of the difference between
schema and models.
Remove Stack.user_creds_id nullable=False parameter
because  we can soft-delete stack, that leads to deletion
user_credits and setting stack.user_creds_id to null
(by cascade).
Remove resource.id default value(in database) as specified
in models.
Since we will have sync check between models and migrations
we need to add missing indexes to models for consistency.

Partially implements bp: db-sync-models-with-migrations

Change-Id: Iabc4aced0a95e29cea9c48abc4c31be98e8ff9b1