When open_urlresource() fails, HTTPException is another possible error

Lib/test/test_multibytecodec_support.py

@@ -6,6 +6,7 @@
 
 import sys, codecs
 import unittest, re
+from httplib import HTTPException
 from test import test_support
 from StringIO import StringIO
 
@@ -268,7 +269,7 @@ class TestBase_Mapping(unittest.TestCase):
         unittest.TestCase.__init__(self, *args, **kw)
         try:
             self.open_mapping_file() # test it to report the error early
-        except IOError:
+        except (IOError, HTTPException):
             self.skipTest("Could not retrieve "+self.mapfileurl)
 
     def open_mapping_file(self):