Orchestration tests to use admin user, demo tenant.

Heat tests have unique credentials requirements, so the identity admin
tenant cannot be used.

These requirements are:
- (username=admin) must be an admin user with authority to create
  other users
- (tenant_name=demo) tenant must have a private quantum network
  with dhcp enabled

Change-Id: I1e9a541ac46cd50faeb8f59196b6e17e202135c1
diff --git a/tempest/clients.py b/tempest/clients.py
index a5c7b4d..d7a740a 100644
--- a/tempest/clients.py
+++ b/tempest/clients.py
@@ -399,5 +399,5 @@
         base = super(OrchestrationManager, self)
         base.__init__(conf.identity.admin_username,
                       conf.identity.admin_password,
-                      conf.identity.admin_tenant_name,
+                      conf.identity.tenant_name,
                       interface=interface)