Fix stress test which was not changed to receive one client value

Change-Id: I186f2827c91d8b1eabd0769dda4765a973bf42b4
Closes-Bug: 1413980
diff --git a/tempest/stress/actions/volume_create_delete.py b/tempest/stress/actions/volume_create_delete.py
index b1c5bb7..93402d9 100644
--- a/tempest/stress/actions/volume_create_delete.py
+++ b/tempest/stress/actions/volume_create_delete.py
@@ -20,8 +20,8 @@
         name = data_utils.rand_name("volume")
         self.logger.info("creating %s" % name)
         volumes_client = self.manager.volumes_client
-        _, volume = volumes_client.create_volume(size=1,
-                                                 display_name=name)
+        volume = volumes_client.create_volume(size=1,
+                                              display_name=name)
         vol_id = volume['id']
         volumes_client.wait_for_volume_status(vol_id, 'available')
         self.logger.info("created %s" % volume['id'])