Use six.moves.urllib.parse instead of urlparse

To keep Python 3.x compatibility, use six.moves.urllib.parse
to replace urlparse.

Add six as a dependency in test_requirements.txt

Change-Id: Ia6cd042970c2d4e5d418a39e25bab32b4d93c544
diff --git a/tests/test_scheduler.py b/tests/test_scheduler.py
index 9787ae1..013aafa 100755
--- a/tests/test_scheduler.py
+++ b/tests/test_scheduler.py
@@ -34,11 +34,11 @@
 import time
 import urllib
 import urllib2
-import urlparse
 
 import git
 import gear
 import fixtures
+import six.moves.urllib.parse as urlparse
 import statsd
 import testtools