TrivialFix: Remove cfg import unused

This patch removes cfg import unused in

kingbird/db/sqlalchemy/api.py
kingbird/db/sqlalchemy/models.py
kingbird/engine/kingbird_lock.py

Change-Id: I779f60cd0e7b2a4d85c1a344544279fe4fe646ac

kingbird/db/sqlalchemy/api.py

@@ -20,7 +20,6 @@ Implementation of SQLAlchemy backend.
 import sys
 import threading
 
-from oslo_config import cfg
 from oslo_db import api as oslo_db_api
 from oslo_db.sqlalchemy import enginefacade
 
@@ -36,8 +35,6 @@ from kingbird.db.sqlalchemy import models
 
 LOG = logging.getLogger(__name__)
 
-CONF = cfg.CONF
-
 _facade = None
 
 _main_context_manager = None

kingbird/db/sqlalchemy/models.py

@@ -16,14 +16,12 @@
 SQLAlchemy models for kingbird data.
 """
 
-from oslo_config import cfg
 from oslo_db.sqlalchemy import models
 
 from sqlalchemy.orm import session as orm_session
 from sqlalchemy import (Column, Integer, String, Boolean, schema)
 from sqlalchemy.ext.declarative import declarative_base
 
-CONF = cfg.CONF
 BASE = declarative_base()