remove tearDownClass in test_quotas.py

There is no need for the functionality of the tearDownClass in the
api/compute/admin/test_quotas.py, becase it's already included in the base
class. So it should be removed.

Change-Id: Ic0e145952cc143d65291258fc9567807ca051596
closes-bug: #1239722
diff --git a/tempest/api/compute/admin/test_quotas.py b/tempest/api/compute/admin/test_quotas.py
index f55f152..e744200 100644
--- a/tempest/api/compute/admin/test_quotas.py
+++ b/tempest/api/compute/admin/test_quotas.py
@@ -52,15 +52,6 @@
                                      'instances', 'security_group_rules',
                                      'cores', 'security_groups'))
 
-    @classmethod
-    def tearDownClass(cls):
-        for server in cls.servers:
-            try:
-                cls.servers_client.delete_server(server['id'])
-            except exceptions.NotFound:
-                continue
-        super(QuotasAdminTestJSON, cls).tearDownClass()
-
     @attr(type='smoke')
     def test_get_default_quotas(self):
         # Admin can get the default resource quota set for a tenant