Remove unnecessary class variables

Some variables in volume quota tests needn't be class variables,
so this is to change them to local variables.

Change-Id: Iabbeb5ea4bcdfb840dd974490a3648614443309b
diff --git a/tempest/api/volume/admin/test_volume_quotas.py b/tempest/api/volume/admin/test_volume_quotas.py
index 61a6df4..e6d77e6 100644
--- a/tempest/api/volume/admin/test_volume_quotas.py
+++ b/tempest/api/volume/admin/test_volume_quotas.py
@@ -48,11 +48,10 @@
         # Save the current set of quotas so that some tests may use it
         # to restore the quotas to their original values after they are
         # done.
-        cls.original_quota_set = (cls.admin_quotas_client.show_quota_set(
+        original_quota_set = (cls.admin_quotas_client.show_quota_set(
             cls.demo_tenant_id)['quota_set'])
         cls.cleanup_quota_set = dict(
-            (k, v) for k, v in cls.original_quota_set.items()
-            if k in QUOTA_KEYS)
+            (k, v) for k, v in original_quota_set.items() if k in QUOTA_KEYS)
 
     @decorators.idempotent_id('59eada70-403c-4cef-a2a3-a8ce2f1b07a0')
     def test_list_quotas(self):
diff --git a/tempest/api/volume/admin/test_volume_quotas_negative.py b/tempest/api/volume/admin/test_volume_quotas_negative.py
index f50f336..7b5cd68 100644
--- a/tempest/api/volume/admin/test_volume_quotas_negative.py
+++ b/tempest/api/volume/admin/test_volume_quotas_negative.py
@@ -38,14 +38,12 @@
         # to restore the quotas to their original values after the tests
         # from this class are done. This is needed just in case Tempest is
         # configured to use pre-provisioned projects/user accounts.
-        cls.original_quota_set = (cls.admin_quotas_client.show_quota_set(
+        original_quota_set = (cls.admin_quotas_client.show_quota_set(
             cls.demo_tenant_id)['quota_set'])
-        cls.cleanup_quota_set = dict(
-            (k, v) for k, v in cls.original_quota_set.items()
-            if k in QUOTA_KEYS)
+        cleanup_quota_set = dict(
+            (k, v) for k, v in original_quota_set.items() if k in QUOTA_KEYS)
         cls.addClassResourceCleanup(cls.admin_quotas_client.update_quota_set,
-                                    cls.demo_tenant_id,
-                                    **cls.cleanup_quota_set)
+                                    cls.demo_tenant_id, **cleanup_quota_set)
 
         cls.shared_quota_set = {'gigabytes': 2 * CONF.volume.volume_size,
                                 'volumes': 1}
diff --git a/tempest/api/volume/admin/test_volume_snapshot_quotas_negative.py b/tempest/api/volume/admin/test_volume_snapshot_quotas_negative.py
index 74eb792..ff5e7e2 100644
--- a/tempest/api/volume/admin/test_volume_snapshot_quotas_negative.py
+++ b/tempest/api/volume/admin/test_volume_snapshot_quotas_negative.py
@@ -44,14 +44,12 @@
         # to restore the quotas to their original values after the tests
         # from this class are done. This is needed just in case Tempest is
         # configured to use pre-provisioned projects/user accounts.
-        cls.original_quota_set = (cls.admin_quotas_client.show_quota_set(
+        original_quota_set = (cls.admin_quotas_client.show_quota_set(
             cls.demo_tenant_id)['quota_set'])
-        cls.cleanup_quota_set = dict(
-            (k, v) for k, v in cls.original_quota_set.items()
-            if k in QUOTA_KEYS)
+        cleanup_quota_set = dict(
+            (k, v) for k, v in original_quota_set.items() if k in QUOTA_KEYS)
         cls.addClassResourceCleanup(cls.admin_quotas_client.update_quota_set,
-                                    cls.demo_tenant_id,
-                                    **cls.cleanup_quota_set)
+                                    cls.demo_tenant_id, **cleanup_quota_set)
 
         cls.default_volume_size = CONF.volume.volume_size
         cls.shared_quota_set = {'gigabytes': 3 * cls.default_volume_size,