Create database from models for SQLite
Create database from models for SQLite

Alembic does not support SQLite, and we don't recommend to use SQLite
in production deployments, so migrations are rarely needed for SQLite.
So we don't bother about working around SQLite limitations, and create
database from models when it is in use. Of course, we still use
alembic to migrate schema on 'real' databases.

Change-Id: I8237a29c7bf5b60136bb1b72fd029fe9ce1abe1f

openstack/taskflow,junneyang/taskflow,pombredanne/taskflow-1,varunarya10/taskflow,jimbobhickville/taskflow,openstack/taskflow,citrix-openstack-build/taskflow,pombredanne/taskflow-1,junneyang/taskflow,jimbobhickville/taskflow,varunarya10/taskflow,citrix-openstack-build/taskflow