Merged revisions 82850 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/branches/py3k

........
  r82850 | alexander.belopolsky | 2010-07-13 10:50:16 -0400 (Tue, 13 Jul 2010) | 1 line

  Set sys.modules[name] to None instead of 0 to block module import.
........

Lib/test/test_support.py

@@ -105,7 +105,7 @@ def _save_and_block_module(name, orig_modules):
         orig_modules[name] = sys.modules[name]
     except KeyError:
         saved = False
-    sys.modules[name] = 0
+    sys.modules[name] = None
     return saved