Use import from six.moves to import the queue module

The name of the synchronized queue class is queue instead of
Queue in Python3.

Change-Id: I89ea14e8d17cd37706752700cedb66b28d347fa2
diff --git a/tests/base.py b/tests/base.py
index 01b42f2..61ee912 100755
--- a/tests/base.py
+++ b/tests/base.py
@@ -21,7 +21,7 @@
 import logging
 import os
 import pprint
-import Queue
+from six.moves import queue as Queue
 import random
 import re
 import select