Remove six[7]

Since our code will only support py3. So remove six is necessary.

Change-Id: I3738118b1898421ee41e9e2902c255ead73f3915

watcher/tests/api/v1/test_strategies.py

@@ -11,10 +11,10 @@
 #    limitations under the License.
 
 import mock
+from urllib import parse as urlparse
 
 from oslo_config import cfg
 from oslo_serialization import jsonutils
-from six.moves.urllib import parse as urlparse
 
 from watcher.common import utils
 from watcher.decision_engine import rpcapi as deapi