delete the duplicated variable definition

A duplicated variable definition is introduced by the early merge today
which should be fixed.

Change-Id: I1aef41d1002867988c05dbab2317365893f58569
Closes-Bug: #1237273
diff --git a/tempest/api/compute/admin/test_servers.py b/tempest/api/compute/admin/test_servers.py
index 2029a2e..1b346f1 100644
--- a/tempest/api/compute/admin/test_servers.py
+++ b/tempest/api/compute/admin/test_servers.py
@@ -33,11 +33,8 @@
     def setUpClass(cls):
         super(ServersAdminTestJSON, cls).setUpClass()
         cls.client = cls.os_adm.servers_client
-        cls.flavors_client = cls.os_adm.flavors_client
-
         cls.non_adm_client = cls.servers_client
         cls.flavors_client = cls.os_adm.flavors_client
-
         cls.identity_client = cls._get_identity_admin_client()
         tenant = cls.identity_client.get_tenant_by_name(
             cls.client.tenant_name)