prepare future tempest breakage

Tempest is going to break the API without deprecation path, one more
time.

http://lists.openstack.org/pipermail/openstack-dev/2017-March/113074.html

This change copies the tempest module that will be removed soon, until
the API is available.

Change-Id: I22d1495882d28f8bb9f120d5dfeb4e107b22fd37
diff --git a/ceilometer/tests/tempest/scenario/test_autoscaling.py b/ceilometer/tests/tempest/scenario/test_autoscaling.py
index 9da1449..38cc153 100644
--- a/ceilometer/tests/tempest/scenario/test_autoscaling.py
+++ b/ceilometer/tests/tempest/scenario/test_autoscaling.py
@@ -15,7 +15,8 @@
 
 from gabbi import driver
 from tempest import config
-from tempest.scenario import manager
+
+from ceilometer.tests.tempest.scenario import manager
 
 
 class TestAutoscalingGabbi(manager.ScenarioTest):