use synchronizers.openstack.openstacksyncstep instead of synchronizers.base.openstacksyncstep

Change-Id: I0e315695cb0b38ce56368721a0b4ea131ae339d4
diff --git a/xos/synchronizer/steps/sync_controller_images.py b/xos/synchronizer/steps/sync_controller_images.py
index c1e5136..dbda082 100644
--- a/xos/synchronizer/steps/sync_controller_images.py
+++ b/xos/synchronizer/steps/sync_controller_images.py
@@ -3,7 +3,7 @@
 from collections import defaultdict
 from django.db.models import F, Q
 from xos.config import Config
-from synchronizers.base.openstacksyncstep import OpenStackSyncStep
+from synchronizers.openstack.openstacksyncstep import OpenStackSyncStep
 from synchronizers.base.syncstep import *
 from core.models import Controller
 from core.models import Image, ControllerImages