storage: add activity logging to destroy method

circle/storage/models.py

@@ -204,7 +204,8 @@ class Disk(TimeStampedModel):
         if self.destroyed:
             return False
 
-        # TODO add activity logging
+        with disk_activity(code_suffix='destroy', disk=self,
+                           task_uuid=task_uuid, user=user):
             self.destroyed = timezone.now()
             self.save()