adopt namespace-less oslo imports

oslo.config is now deprecated, so switching
from oslo.config to right package oslo_config.

similarly oslo.serialization also deprecated, it
is also switched to oslo_serialization from
oslo.serialization.

Change-Id: I52eff48a17a555750379e4ca6bb024fc71a4efeb
Closes-Bug: #1409733

openstack_dashboard/api/rest/utils.py

@@ -19,7 +19,7 @@ from django.conf import settings
 from django import http
 from django.utils import decorators
 
-from oslo.serialization import jsonutils
+from oslo_serialization import jsonutils
 
 from horizon import exceptions
 

openstack_dashboard/policy.py

@@ -20,7 +20,7 @@ import os.path
 
 from django.conf import settings
 from openstack_auth import utils as auth_utils
-from oslo.config import cfg
+from oslo_config import cfg
 
 from openstack_dashboard.openstack.common import policy
 

openstack_dashboard/test/integration_tests/config.py

@@ -12,7 +12,7 @@
 
 import os
 
-from oslo.config import cfg
+from oslo_config import cfg
 
 
 DashboardGroup = [