Do not import threading.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@3131 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ZSQLCatalog/ZSQLCatalog.py

@@ -28,7 +28,7 @@ from AccessControl.Permission import name_trans
 from SQLCatalog import Catalog, CatalogError
 from AccessControl import ClassSecurityInfo, getSecurityManager
 from AccessControl.DTML import RestrictedDTML
-import string, os, sys, types, threading
+import string, os, sys, types
 
 from zLOG import LOG