Fix Py26 test cases

Author: wizzat

test/test_producer_integration.py

@@ -144,7 +144,7 @@ def test_simple_producer(self):
 
     @kafka_versions("all")
     def test_produce__new_topic_fails_with_reasonable_error(self):
-        new_topic = 'new_topic_{}'.format(str(uuid.uuid4()))
+        new_topic = 'new_topic_{guid}'.format(guid = str(uuid.uuid4()))
         producer = SimpleProducer(self.client)
 
         # At first it doesn't exist