[Django 1.9] Stop using django.utils.importlib

Horizon still uses django.utils.importlib which is removed from Django
1.9. We should use:
from importlib import import_module

instead of:
from django.utils.importlib import import_module

Change-Id: I422e14546468cb9c5627e746023948aab107a338
Closes-Bug: #1534522
Partially-Implements: blueprint drop-dj17
Co-Authored-By: Rob Cresswell <robert.cresswell@outlook.com>

horizon/base.py

@@ -35,9 +35,9 @@ from django.core.urlresolvers import reverse
 from django.utils.encoding import python_2_unicode_compatible
 from django.utils.functional import empty
 from django.utils.functional import SimpleLazyObject  # noqa
-from django.utils.importlib import import_module  # noqa
 from django.utils.module_loading import module_has_submodule  # noqa
 from django.utils.translation import ugettext_lazy as _
+from importlib import import_module
 import six
 
 from horizon import conf

horizon/management/commands/startdash.py

@@ -16,7 +16,7 @@ import os
 
 from django.core.management.base import CommandError  # noqa
 from django.core.management.templates import TemplateCommand  # noqa
-from django.utils.importlib import import_module  # noqa
+from importlib import import_module
 
 import horizon
 

horizon/management/commands/startpanel.py

@@ -16,7 +16,7 @@ import os
 
 from django.core.management.base import CommandError  # noqa
 from django.core.management.templates import TemplateCommand  # noqa
-from django.utils.importlib import import_module  # noqa
+from importlib import import_module
 
 import horizon
 

horizon/test/tests/base.py

@@ -21,7 +21,7 @@ from django.conf import settings
 from django.contrib.auth.models import User  # noqa
 from django.core.exceptions import ImproperlyConfigured  # noqa
 from django.core import urlresolvers
-from django.utils.importlib import import_module  # noqa
+from importlib import import_module
 from six import moves
 
 import six

horizon/workflows/base.py

@@ -24,8 +24,8 @@ from django.template.defaultfilters import linebreaks  # noqa
 from django.template.defaultfilters import safe  # noqa
 from django.template.defaultfilters import slugify  # noqa
 from django.utils.encoding import force_text
-from django.utils.importlib import import_module  # noqa
 from django.utils.translation import ugettext_lazy as _
+from importlib import import_module
 import six
 
 from horizon import base

openstack_dashboard/contrib/developer/theme_preview/tests.py

@@ -16,7 +16,7 @@
 from django.conf import settings
 from django.core import urlresolvers
 from django.core.urlresolvers import reverse
-from django.utils.importlib import import_module  # noqa
+from importlib import import_module
 from six import moves
 
 from horizon import base

openstack_dashboard/test/helpers.py

@@ -22,8 +22,6 @@ from functools import wraps  # noqa
 import os
 import unittest
 
-from ceilometerclient.v2 import client as ceilometer_client
-from cinderclient import client as cinder_client
 import django
 from django.conf import settings
 from django.contrib.messages.storage import default_storage  # noqa
@@ -31,10 +29,13 @@ from django.core.handlers import wsgi
 from django.core import urlresolvers
 from django.test.client import RequestFactory  # noqa
 from django.test import utils as django_test_utils
-from django.utils.importlib import import_module  # noqa
+
+from ceilometerclient.v2 import client as ceilometer_client
+from cinderclient import client as cinder_client
 import glanceclient
 from heatclient import client as heat_client
 import httplib2
+from importlib import import_module
 from keystoneclient.v2_0 import client as keystone_client
 import mock
 from mox3 import mox

openstack_dashboard/utils/settings.py

@@ -11,11 +11,10 @@
 #    under the License.
 
 import collections
+from importlib import import_module
 import logging
 import os
 import pkgutil
-
-from django.utils import importlib
 import six
 
 from horizon.utils import file_discovery as fd
@@ -27,7 +26,7 @@ def import_submodules(module):
     for loader, name, ispkg in pkgutil.iter_modules(module.__path__,
                                                     module.__name__ + '.'):
         try:
-            submodule = importlib.import_module(name)
+            submodule = import_module(name)
         except ImportError as e:
             # FIXME: Make the errors non-fatal (do we want that?).
             logging.warning("Error importing %s" % name)
@@ -120,7 +119,7 @@ def update_dashboards(modules, horizon_config, installed_apps):
 
         if config.get('AUTO_DISCOVER_STATIC_FILES', False):
             for _app in _apps:
-                module = importlib.import_module(_app)
+                module = import_module(_app)
                 base_path = os.path.join(module.__path__[0], 'static/')
                 fd.populate_horizon_config(horizon_config, base_path)