Fix Typo: test/test_mtu.py

first argument of a method should be named 'self'.

Change-Id: Iab84a333baba9b9dfb6ffd6da66df4da331a6b11
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>

test/test_mtu.py

@@ -46,9 +46,9 @@ class TestMTU(VppTestCase):
         cls.create_pg_interfaces(range(2))
         cls.interfaces = list(cls.pg_interfaces)
 
-    def setUp(cls):
-        super(TestMTU, cls).setUp()
-        for i in cls.interfaces:
+    def setUp(self):
+        super(TestMTU, self).setUp()
+        for i in self.interfaces:
             i.admin_up()
             i.config_ip4()
             i.config_ip6()