Possible Release Blocker

A number of proxy test cases in test_urllib2 are now failing with:

ERROR: test_proxy (test.test_urllib2.HandlerTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File 
"/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/test/te
st_urllib2.py", line 940, in test_proxy
    r = o.open(req)
  File 
"/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/urllib2
.py", line 389, in open
    response = self._open(req, data)
  File 
"/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/urllib2
.py", line 407, in _open
    '_open', req)
  File 
"/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/urllib2
.py", line 367, in _call_chain
    result = func(*args)
  File 
"/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/urllib2
.py", line 696, in <lambda>
    meth(r, proxy, type))
  File 
"/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/urllib2
.py", line 705, in proxy_open
    if req.host and proxy_bypass(req.host):
  File 
"/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/urllib.
py", line 1398, in proxy_bypass
    return proxy_bypass_macosx_sysconf(host)
  File 
"/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/urllib.
py", line 1367, in proxy_bypass_macosx_sysconf
    if hostIP is None:
UnboundLocalError: local variable 'hostIP' referenced before assignment

The root cause is the problem identified in Issue7044.  This is now 
showing up in test_urllib2 because of the changes in urllib2 introduced 
by Issue6894 which was checked into the release-26maint branch during 
the window between the release of 2.6.3 and the freezing for 2.6.4.