lp-registration is not compatible with python-2.7

the problem is potentially linked to my instalation (with python2.7) I've install bzr from source and it compiles perfectly.
but then it fails to load a branch.

It's maybe smtg stupid, sorry in advance if it is,

Olivier

bzr: ERROR: exceptions.AttributeError: addinfourl instance has no attribute 'getheader'

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/site-packages/bzrlib/commands.py", line 853, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/commands.py", line 1055, in run_bzr
    ret = run(*run_argv)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/commands.py", line 661, in run_argv_aliases
    return self.run_direct(**all_cmd_args)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/commands.py", line 665, in run_direct
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/cleanup.py", line 122, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/cleanup.py", line 156, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/builtins.py", line 1194, in run
    from_location)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/bzrdir.py", line 956, in open_tree_or_branch
    bzrdir = klass.open(location)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/bzrdir.py", line 840, in open
    t = get_transport(base, possible_transports=possible_transports)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/lazy_import.py", line 125, in __call__
    return obj(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/transport/__init__.py", line 1559, in get_transport
    base = directories.dereference(base)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/directory_service.py", line 58, in dereference
    return service().look_up(name, url)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/plugins/launchpad/lp_directory.py", line 60, in look_up
    return self._resolve(url)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/plugins/launchpad/lp_directory.py", line 70, in _resolve
    result = resolve.submit(service)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/plugins/launchpad/lp_registration.py", line 275, in submit
    self._authenticated)
  File "/usr/local/lib/python2.7/site-packages/bzrlib/plugins/launchpad/lp_registration.py", line 198, in send_request
    result = method(*method_params)
  File "/usr/local/lib/python2.7/xmlrpclib.py", line 1224, in __call__
    return self.__send(self.__name, args)
  File "/usr/local/lib/python2.7/xmlrpclib.py", line 1570, in __request
    verbose=self.__verbose
  File "/usr/local/lib/python2.7/site-packages/bzrlib/plugins/launchpad/lp_registration.py", line 78, in request
    return self.parse_response(response)
  File "/usr/local/lib/python2.7/xmlrpclib.py", line 1449, in parse_response
    if response.getheader("Content-Encoding", "") == "gzip":
AttributeError: addinfourl instance has no attribute 'getheader'

bzr 2.1.2 on python 2.7.0 (Darwin-8.11.0-Power_Macintosh-powerpc-32bit)
arguments: ['/usr/local/bin/bzr', 'branch', 'lp:madgraph5']
encoding: 'UTF-8', fsenc: 'utf-8', lang: 'en_US.UTF-8'
plugins:
  launchpad /usr/local/lib/python2.7/site-packages/bzrlib/plugins/launchpad [2.1.2]
  netrc_credential_store /usr/local/lib/python2.7/site-packages/bzrlib/plugins/netrc_credential_store [2.1.2]
  news_merge /usr/local/lib/python2.7/site-packages/bzrlib/plugins/news_merge [2.1.2]