Fix for volume multiattach check

Related-prod: PRODX-26176

Change-Id: I29fe0f1c216ff39adef38969bef44b2aa2f47f76
diff --git a/tempest/api/volume/test_volumes_negative.py b/tempest/api/volume/test_volumes_negative.py
index f0151e5..6d98cb6 100644
--- a/tempest/api/volume/test_volumes_negative.py
+++ b/tempest/api/volume/test_volumes_negative.py
@@ -257,8 +257,7 @@
         """Test reserving already reserved volume should fail"""
 
         # Skip test if the volume has "multiattach" property
-        volume = self.volumes_client.show_volume(self.volume['id'])
-        if volume['multiattach']:
+        if self.volume['multiattach']:
             raise self.skipException('Reserving multiattach volumes is not'
                                      ' supported.')