Migrate computev2 API tests to resource_* fixtures

Partially-implements bp:resource-cleanup

Change-Id: I59eb2d9789368c812282ce12ae7e571be720badb
diff --git a/tempest/api/compute/admin/test_aggregates_negative.py b/tempest/api/compute/admin/test_aggregates_negative.py
index 690f2ab..ef6752b 100644
--- a/tempest/api/compute/admin/test_aggregates_negative.py
+++ b/tempest/api/compute/admin/test_aggregates_negative.py
@@ -27,8 +27,8 @@
     """
 
     @classmethod
-    def setUpClass(cls):
-        super(AggregatesAdminNegativeTestJSON, cls).setUpClass()
+    def resource_setup(cls):
+        super(AggregatesAdminNegativeTestJSON, cls).resource_setup()
         cls.client = cls.os_adm.aggregates_client
         cls.user_client = cls.aggregates_client
         cls.aggregate_name_prefix = 'test_aggregate_'