Drop dependency on log from oslo db code

Openstack common log module registers a few oslo.config options,
which can possibly lead to unpleasant issues (DuplicateOptError)
when we split oslo.db from oslo-incubator into a separate library
and reuse both log and oslo.db in target projects.

We don't use for example, any of the special formatting supported by
ContextAdaptor so we can use logging module from python standart library
instead of common log module.

Related to blueprint oslo-db-lib

Change-Id: I6ec426274eb3b603dbbc894762edb97515a618b2

openstack/common/db/sqlalchemy/migration_cli/ext_migrate.py

@@ -10,12 +10,12 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import logging
 import os
 
 from openstack.common.db.sqlalchemy import migration
 from openstack.common.db.sqlalchemy.migration_cli import ext_base
 from openstack.common.gettextutils import _  # noqa
-from openstack.common import log as logging
 
 
 LOG = logging.getLogger(__name__)

openstack/common/db/sqlalchemy/session.py

@@ -271,6 +271,7 @@ Efficient use of soft deletes:
 """
 
 import functools
+import logging
 import os.path
 import re
 import time
@@ -285,7 +286,6 @@ from sqlalchemy.sql.expression import literal_column
 
 from openstack.common.db import exception
 from openstack.common.gettextutils import _
-from openstack.common import log as logging
 from openstack.common import timeutils
 
 sqlite_db_opts = [

openstack/common/db/sqlalchemy/test_migrations.py

@@ -15,6 +15,7 @@
 #    under the License.
 
 import functools
+import logging
 import os
 import subprocess
 
@@ -25,7 +26,6 @@ import sqlalchemy.exc
 
 from openstack.common.db.sqlalchemy import utils
 from openstack.common.gettextutils import _
-from openstack.common import log as logging
 from openstack.common.py3kcompat import urlutils
 from openstack.common import test
 

openstack/common/db/sqlalchemy/utils.py

@@ -16,6 +16,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import logging
 import re
 
 from migrate.changeset import UniqueConstraint
@@ -37,8 +38,6 @@ from sqlalchemy import Table
 from sqlalchemy.types import NullType
 
 from openstack.common.gettextutils import _
-
-from openstack.common import log as logging
 from openstack.common import timeutils