Modify the comment for backups_client in v1

modify the comment for the file backup_client.py in v1

Change-Id: I68db479cb0023cb8271a0789e6d8eca8e0d14f8e
diff --git a/tempest/lib/services/volume/v1/backups_client.py b/tempest/lib/services/volume/v1/backups_client.py
index edc5dda..2289253 100644
--- a/tempest/lib/services/volume/v1/backups_client.py
+++ b/tempest/lib/services/volume/v1/backups_client.py
@@ -83,6 +83,9 @@
 
     def import_backup(self, **kwargs):
         """Import backup metadata record."""
+        # TODO(linanbj): Current api-site doesn't contain this API description.
+        # After fixing the api-site, we need to fix here also for putting the
+        # link to api-site.
         post_body = json.dumps({'backup-record': kwargs})
         resp, body = self.post("backups/import_record", post_body)
         body = json.loads(body)