Fix response of database Limits & Versions client

This patch converts the json response returned to python object before
passing to ResponseBody.

Change-Id: Ic616b718b5bdcfb18e141548fd00ea59320f5b5d
diff --git a/tempest/services/database/json/limits_client.py b/tempest/services/database/json/limits_client.py
index 9358a33..da495d7 100644
--- a/tempest/services/database/json/limits_client.py
+++ b/tempest/services/database/json/limits_client.py
@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_serialization import jsonutils as json
 from six.moves.urllib import parse as urllib
 
 from tempest.common import service_client
@@ -27,4 +28,5 @@
             url += '?%s' % urllib.urlencode(params)
         resp, body = self.get(url)
         self.expected_success(200, resp.status)
+        body = json.loads(body)
         return service_client.ResponseBody(resp, body)
diff --git a/tempest/services/database/json/versions_client.py b/tempest/services/database/json/versions_client.py
index 43d253b..7a560d9 100644
--- a/tempest/services/database/json/versions_client.py
+++ b/tempest/services/database/json/versions_client.py
@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_serialization import jsonutils as json
 from six.moves.urllib import parse as urllib
 
 from tempest.common import service_client
@@ -43,4 +44,5 @@
 
         resp, body = self.get(url)
         self.expected_success(200, resp.status)
+        body = json.loads(body)
         return service_client.ResponseBody(resp, body)