Configure driver for postgres

Avoid the following warning seen in e.g. nova unit tests:

  WARNING oslo_db.sqlalchemy.engines [-] URL postgresql://.../foo does
  not contain a '+drivername' portion, and will make use of a default
  driver.
  A full dbname+drivername:// protocol is recommended.

The 'psycopg2' driver is chosen since this is the default for SQLAlchemy
[1] and therefore what we're currently using.

[1] https://docs.sqlalchemy.org/en/14/core/engines.html#postgresql



Change-Id: I0f8f358a49a83366d7dec17e7bac346453f3027b
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

oslo_db/sqlalchemy/provision.py

@@ -577,8 +577,7 @@ class SQLiteBackendImpl(BackendImpl):
 @BackendImpl.impl.dispatch_for("postgresql")
 class PostgresqlBackendImpl(BackendImpl):
     def create_opportunistic_driver_url(self):
-        return "postgresql://openstack_citest:openstack_citest"\
-            "@localhost/postgres"
+        return "postgresql+psycopg2://openstack_citest:openstack_citest@localhost/postgres"  # noqa: E501
 
     def create_named_database(self, engine, ident, conditional=False):
         with engine.connect().execution_options(