Tests Cleanup: Fix missing calls to setUpClass/tearDownClass.

Continuation/Part 2 of https://gerrit.fd.io/r/#/c/17092/

Change-Id: Id0122d84eaf2c05d29e5be63a594d5e528ee7c9a
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
diff --git a/test/test_srv6_as.py b/test/test_srv6_as.py
index 6b8e23c..108fcdb 100755
--- a/test/test_srv6_as.py
+++ b/test/test_srv6_as.py
@@ -27,6 +27,10 @@
     def setUpClass(self):
         super(TestSRv6, self).setUpClass()
 
+    @classmethod
+    def tearDownClass(cls):
+        super(TestSRv6, cls).tearDownClass()
+
     def setUp(self):
         """ Perform test setup before each test case.
         """