Add restore method for vsg wan/lan toggle tests for vcpe dhcp ip.
Get dhcp ip for the first firewall test before subsequent tests.
Other tests need to do the same.

Change-Id: Iacc07242915bca02e1d6a953575777d98220f466
diff --git a/src/test/utils/CordTestConfig.py b/src/test/utils/CordTestConfig.py
index 74c4889..45527b6 100644
--- a/src/test/utils/CordTestConfig.py
+++ b/src/test/utils/CordTestConfig.py
@@ -26,7 +26,7 @@
                 self.context = context
 
     #reset the context on exit
-    def afterContext(self, context):
+    def stopContext(self, context):
         if inspect.isclass(context) and issubclass(context, unittest.TestCase):
             if context.__name__.endswith('exchange'):
                 self.context = None