Remove unused logging import and LOG global var

In some modules the global LOG is not used any more. And the import
of logging is not used. This patch removes the unused logging import
and LOG vars.

Change-Id: I794ee719d76f04e70154cf67f726152fbb1ba15a

watcher/db/sqlalchemy/api.py

@@ -21,7 +21,6 @@ from oslo_config import cfg
 from oslo_db import exception as db_exc
 from oslo_db.sqlalchemy import session as db_session
 from oslo_db.sqlalchemy import utils as db_utils
-from oslo_log import log
 from sqlalchemy.orm import exc
 
 from watcher import _i18n
@@ -35,7 +34,6 @@ from watcher.objects import audit as audit_objects
 from watcher.objects import utils as objutils
 
 CONF = cfg.CONF
-LOG = log.getLogger(__name__)
 _ = _i18n._
 
 _FACADE = None