Added teardown method to delete certificate

Change-Id: I77a20586856b97a4578fbede2086b31a9e69eba8
Signed-off-by: Rahul Maheshwari <rahulmaheshwari@in.ibm.com>
diff --git a/test_lists/skip_test_witherspoon b/test_lists/skip_test_witherspoon
index 37332e8..5dd743d 100644
--- a/test_lists/skip_test_witherspoon
+++ b/test_lists/skip_test_witherspoon
@@ -11,6 +11,7 @@
 # NA test case for Witherspoon
 -e io_board_Present
 -e io_board_Fault
+-e Certificate_Test
 # System LED test cases which are NA for Witherspoon system.
 -e Test_Heartbeat_LED_And_Verify_Via_REST
 -e Test_Beep_LED_And_Verify_Via_REST