Remove six[7]

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

Change-Id: I3738118b1898421ee41e9e2902c255ead73f3915

watcher/decision_engine/datasources/grafana.py

@@ -16,9 +16,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from urllib import parse as urlparse
+
 from oslo_config import cfg
 from oslo_log import log
-import six.moves.urllib.parse as urlparse
 
 from watcher.common import clients
 from watcher.common import exception