Switch from using custom urlparse import logic to six

This commit removes the try except logic in auth.py to import urlparse
on either python2 or python3 to use six instead. Six already provides
an interface to use urlparse the same way on either python2 or python3
which is a bit cleaner.

Change-Id: I964586af4b2df63ae81b09ac1c3f1397b0250b80

tempest_lib/auth.py

@@ -17,13 +17,10 @@ import abc
 import copy
 import datetime
 import re
-try:
-    import urllib.parse as urlparse
-except ImportError:
-    import urlparse
 
 from oslo_log import log as logging
 import six
+from six.moves.urllib import parse as urlparse
 
 from tempest_lib import exceptions
 from tempest_lib.services.identity.v2 import token_client as json_v2id