Enable igmp test to work under voltha.
Also change cordSubscriber voltha test to work with the voltha auto configure.
Import teardown_module as well in other test cases.
The tests that are not supposed to work with voltha or rely on auto configure should set:
VOLTHA_AUTO_CONFIGURE = False
in their test class.

Change-Id: Ibbe60e524d31e7079e0423e9e3c390ee17dee2a7
diff --git a/src/test/scale/scaleTest.py b/src/test/scale/scaleTest.py
index 19740ad..f6a1ee0 100644
--- a/src/test/scale/scaleTest.py
+++ b/src/test/scale/scaleTest.py
@@ -31,7 +31,7 @@
 from CordLogger import CordLogger
 from VSGAccess import VSGAccess
 from CordTestUtils import log_test as log
-from CordTestConfig import setup_module, running_on_ciab
+from CordTestConfig import setup_module, running_on_ciab, teardown_module
 from OnosCtrl import OnosCtrl
 from CordContainer import Onos
 from CordSubscriberUtils import CordSubscriberUtils, XosUtils