Keep py3.X compatibility for urllib.urlencode

For py3.X, urllib has no attr urlencode while python 2 has.
Change urlencode to keep compatibility.

Change-Id: I9fc041d6fd8b65d0a19f38ae1915dcb2a1b42553
Partial-Bug: #1280105
diff --git a/tempest/services/database/json/flavors_client.py b/tempest/services/database/json/flavors_client.py
index 34a91ba..dbb5172 100644
--- a/tempest/services/database/json/flavors_client.py
+++ b/tempest/services/database/json/flavors_client.py
@@ -14,7 +14,7 @@
 #    under the License.
 
 from oslo_serialization import jsonutils as json
-import urllib
+from six.moves import urllib
 
 from tempest.common import service_client
 
@@ -24,7 +24,7 @@
     def list_db_flavors(self, params=None):
         url = 'flavors'
         if params:
-            url += '?%s' % urllib.urlencode(params)
+            url += '?%s' % urllib.parse.urlencode(params)
 
         resp, body = self.get(url)
         self.expected_success(200, resp.status)
diff --git a/tempest/test.py b/tempest/test.py
index 407df3b..c4e93bc 100644
--- a/tempest/test.py
+++ b/tempest/test.py
@@ -19,7 +19,6 @@
 import re
 import sys
 import time
-import urllib
 import uuid
 
 import fixtures
@@ -27,6 +26,7 @@
 from oslo_serialization import jsonutils as json
 from oslo_utils import importutils
 import six
+from six.moves import urllib
 from tempest_lib import decorators
 import testscenarios
 import testtools
@@ -770,7 +770,7 @@
         if not json_dict:
             return url, None
         elif method in ["GET", "HEAD", "PUT", "DELETE"]:
-            return "%s?%s" % (url, urllib.urlencode(json_dict)), None
+            return "%s?%s" % (url, urllib.parse.urlencode(json_dict)), None
         else:
             return url, json.dumps(json_dict)