Check no specific group present in group list

Let's check no specific group present instead of list is empty
in test_group_snapshot_create_show_list_delete.
This maybe a reason of failed test due to some inconsistency.

Closes-Bug: #1869852
Change-Id: I41884567ae07b4d6a28667d2a3a792b63e1a6cfa
diff --git a/tempest/api/volume/admin/test_group_snapshots.py b/tempest/api/volume/admin/test_group_snapshots.py
index 731a055..fb0ad6d 100644
--- a/tempest/api/volume/admin/test_group_snapshots.py
+++ b/tempest/api/volume/admin/test_group_snapshots.py
@@ -113,7 +113,8 @@
         self._delete_group_snapshot(group_snapshot)
         group_snapshots = self.group_snapshots_client.list_group_snapshots()[
             'group_snapshots']
-        self.assertEmpty(group_snapshots)
+        self.assertNotIn((group_snapshot['name'], group_snapshot['id']),
+                         [(m['name'], m['id']) for m in group_snapshots])
 
     @decorators.idempotent_id('eff52c70-efc7-45ed-b47a-4ad675d09b81')
     def test_create_group_from_group_snapshot(self):