Fix pxeconfig to match newer nbhelper changes

Change-Id: I75931ec6c89cca04202cf0faaa1227d8ce633548
diff --git a/scripts/pxeconfig.py b/scripts/pxeconfig.py
index 9f77f9e..97aedab 100644
--- a/scripts/pxeconfig.py
+++ b/scripts/pxeconfig.py
@@ -27,14 +27,14 @@
         },
     }
 
-    args = nbhelper.parse_cli_args(extra_args)
-    nbh = nbhelper.NBHelper(args)
+    args = nbhelper.initialize(extra_args)
+    tenant = nbhelper.NBTenant()
 
     yaml_out = {}
     pxeboot_hosts = []
 
-    prefixes = nbh.all_prefixes()
-    devices = nbhelper.NBDevice.all_devs()
+    prefixes = nbhelper.NBPrefix.all_prefixes()
+    devices = nbhelper.NBDevice.all_objects()
 
     for dev_id, device in devices.items():