fix bugs found by pylint
diff --git a/src/python/oftest/controller.py b/src/python/oftest/controller.py
index df24c89..b23eefa 100644
--- a/src/python/oftest/controller.py
+++ b/src/python/oftest/controller.py
@@ -26,6 +26,7 @@
 
 """
 
+import sys
 import os
 import socket
 import time
@@ -472,7 +473,7 @@
                 self.wakeup()
                 with self.connect_cv:
                     if self.initial_hello:
-                        self.message_send(hello())
+                        self.message_send(ofp.message.hello())
                     self.connect_cv.notify() # Notify anyone waiting
             else:
                 self.logger.error("Could not actively connect to switch %s",
diff --git a/src/python/oftest/help_formatter.py b/src/python/oftest/help_formatter.py
index 0e0a7c9..bd6feb1 100644
--- a/src/python/oftest/help_formatter.py
+++ b/src/python/oftest/help_formatter.py
@@ -7,4 +7,4 @@
             indent = " "*self.current_indent
             return indent + description
         else:
-            return none
+            return None
diff --git a/src/python/oftest/packet.py b/src/python/oftest/packet.py
index 67dffb2..1b43091 100644
--- a/src/python/oftest/packet.py
+++ b/src/python/oftest/packet.py
@@ -4,6 +4,7 @@
 """
 Wrap scapy to satisfy pylint
 """
+import sys
 
 try:
     import scapy.layers.l2
diff --git a/src/python/oftest/testutils.py b/src/python/oftest/testutils.py
index 26c25d3..1d56f79 100644
--- a/src/python/oftest/testutils.py
+++ b/src/python/oftest/testutils.py
@@ -1301,7 +1301,7 @@
     test.assertTrue(reply is not None, "No response to stats request")
     stats.extend(reply.entries)
     while reply.flags & more_flag != 0:
-        reply, pkt = self.controller.poll(exp_msg=ofp.OFPT_STATS_REPLY)
+        reply, pkt = test.controller.poll(exp_msg=ofp.OFPT_STATS_REPLY)
         test.assertTrue(reply is not None, "No response to stats request")
         stats.extend(reply.entries)
     return stats