CLOUDSTACK-9584: Fix intermittent test failure in `test_volumes`

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>

test/integration/component/test_volumes.py

@@ -1261,7 +1261,7 @@ class TestVolumes(cloudstackTestCase):
             zoneid=self.zone.id,
             account=domuser.name,
             domainid=dom.id,
-            diskofferingid=diskoffering[0].id
+            diskofferingid=filter(lambda x: not x.iscustomized, diskoffering)[0].id
         )
         self.assertTrue(
             vol is not None, "volume creation fails in domain %s as user %s" %