Update __all__ for cookielib, csv, os, and urllib2 for objects imported into
the module but exposed as part of the API.
diff --git a/Lib/os.py b/Lib/os.py
index def448f..715ff20 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -28,7 +28,7 @@
_names = sys.builtin_module_names
# Note: more names are added to __all__ later.
-__all__ = ["altsep", "curdir", "pardir", "sep", "pathsep", "linesep",
+__all__ = ["altsep", "curdir", "pardir", "sep", "extsep", "pathsep", "linesep",
"defpath", "name", "path", "devnull",
"SEEK_SET", "SEEK_CUR", "SEEK_END"]