Fix AutoScalingTest test suite error

Fix the credential return value tuple order of Orchestration-
ScenarioTest to match that of its parent class, OfficialClientTest.

Change-Id: Ie60403f17e23cb4843578bd389ae3e0c8b22e4b2
Closes-Bug: #1263220
diff --git a/tempest/scenario/manager.py b/tempest/scenario/manager.py
index 207c542..29a5f56 100644
--- a/tempest/scenario/manager.py
+++ b/tempest/scenario/manager.py
@@ -953,7 +953,7 @@
         username = cls.config.identity.admin_username
         password = cls.config.identity.admin_password
         tenant_name = cls.config.identity.tenant_name
-        return username, tenant_name, password
+        return username, password, tenant_name
 
     def _load_template(self, base_file, file_name):
         filepath = os.path.join(os.path.dirname(os.path.realpath(base_file)),