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/test-requirements.txt b/test-requirements.txt
index 34a7a6b..875a821 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -7,6 +7,7 @@
 discover
 fixtures>=0.3.14
 python-subunit
+six>=1.4.1
 testrepository>=0.0.17
 testtools>=0.9.32
 sphinxcontrib-programoutput