Error while trying to auth to IPv6 keystone URL

Authentication against keystone URLs with an IPv6 address fails.

echo ${OS_AUTH_URL}
http://[fd00::c10d]:8081/openstack/identity/v2.0

nova --debug list

REQ: curl -i http://[fd00::c10d]:8081/openstack/identity/v2.0/tokens -X POST -H "Content-Type: application/json" -H "Accept: application/json" -H "User-Agent: python-novaclient" -d '{"auth": {"tenantName": "default", "passwordCredentials": {"username": "admin", "password": "secret"}}}'

DEBUG (shell:737) Failed to parse: Failed to parse: fd00::c10d:8081
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/novaclient/shell.py", line 734, in main
    OpenStackComputeShell().main(map(strutils.safe_decode, sys.argv[1:]))
  File "/usr/local/lib/python2.7/dist-packages/novaclient/shell.py", line 664, in main
    self.cs.authenticate()
  File "/usr/local/lib/python2.7/dist-packages/novaclient/v1_1/client.py", line 171, in authenticate
    self.client.authenticate()
  File "/usr/local/lib/python2.7/dist-packages/novaclient/client.py", line 329, in authenticate
    auth_url = self._v2_auth(auth_url)
  File "/usr/local/lib/python2.7/dist-packages/novaclient/client.py", line 411, in _v2_auth
    return self._authenticate(url, body)
  File "/usr/local/lib/python2.7/dist-packages/novaclient/client.py", line 423, in _authenticate
    **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/novaclient/client.py", line 195, in _time_request
    resp, body = self.request(url, method, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/novaclient/client.py", line 166, in request
    **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/requests/sessions.py", line 335, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/local/lib/python2.7/dist-packages/requests/sessions.py", line 438, in send
    r = adapter.send(request, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/requests/adapters.py", line 272, in send
    conn = self.get_connection(request.url, proxies)
  File "/usr/local/lib/python2.7/dist-packages/requests/adapters.py", line 199, in get_connection
    conn = self.poolmanager.connection_from_url(url)
  File "/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/poolmanager.py", line 122, in connection_from_url
    u = parse_url(url)
  File "/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/util.py", line 156, in parse_url
    raise LocationParseError("Failed to parse: %s" % url)
LocationParseError: Failed to parse: Failed to parse: fd00::c10d:8081
ERROR: Failed to parse: Failed to parse: fd00::c10d:8081

The curl command works (with --globoff)