test framework: Fix wrapper functions to match API message names.

In preparation to remove the wrappers in vpp_papi_provider.py, ensure
names used in tests match the actual API message names.

Change-Id: I230ca4eb75aa727ff68d702e085a2edbbc6b6d19
Signed-off-by: Ole Troan <ot@cisco.com>
diff --git a/test/test_tcp.py b/test/test_tcp.py
index ff23134..5f2bce5 100644
--- a/test/test_tcp.py
+++ b/test/test_tcp.py
@@ -32,10 +32,10 @@
             table_id += 1
 
         # Configure namespaces
-        self.vapi.app_namespace_add(namespace_id="0",
-                                    sw_if_index=self.loop0.sw_if_index)
-        self.vapi.app_namespace_add(namespace_id="1",
-                                    sw_if_index=self.loop1.sw_if_index)
+        self.vapi.app_namespace_add_del(namespace_id="0",
+                                        sw_if_index=self.loop0.sw_if_index)
+        self.vapi.app_namespace_add_del(namespace_id="1",
+                                        sw_if_index=self.loop1.sw_if_index)
 
     def tearDown(self):
         for i in self.lo_interfaces: