Fix import order to comply with import ordering rules.

Fixes pep8 failures TEMPEST N306 and N301.

Change-Id: I87d6ef4058170da73ff64d4e4a4caf43f8a18046
diff --git a/tempest/services/identity/json/admin_client.py b/tempest/services/identity/json/admin_client.py
index 9e171b6..6c36195 100644
--- a/tempest/services/identity/json/admin_client.py
+++ b/tempest/services/identity/json/admin_client.py
@@ -1,8 +1,9 @@
-from tempest.common.rest_client import RestClient
-from tempest import exceptions
 import httplib2
 import json
 
+from tempest.common.rest_client import RestClient
+from tempest import exceptions
+
 
 class AdminClientJSON(RestClient):