retry builds fails with new python-pygraphviz and LP-lib against python 3.6

[Rik Mills]

kubuntu-retry-builds fails with new python-pygraphviz build against python 3.6

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/pygraphviz/graphviz.py", line 18, in swig_import_helper
    fp, pathname, description = imp.find_module('_graphviz', [dirname(__file__)])
  File "/usr/lib/python3.5/imp.py", line 296, in find_module
    raise ImportError(_ERR_MSG.format(name), name=name)
ImportError: No module named '_graphviz'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/kubuntu-retry-builds", line 27, in <module>
    from lib.kagraph import *
  File "/usr/lib/python3/dist-packages/lib/kagraph.py", line 18, in <module>
    import pygraphviz as pgv
  File "/usr/lib/python3/dist-packages/pygraphviz/__init__.py", line 58, in <module>
    from .agraph import AGraph, Node, Edge, Attribute, ItemAttribute, DotError
  File "/usr/lib/python3/dist-packages/pygraphviz/agraph.py", line 22, in <module>
    from . import graphviz as gv
  File "/usr/lib/python3/dist-packages/pygraphviz/graphviz.py", line 28, in <module>
    _graphviz = swig_import_helper()
  File "/usr/lib/python3/dist-packages/pygraphviz/graphviz.py", line 20, in swig_import_helper
    import _graphviz

[Rik Mills (rikmills)]

Turning off the logging to skip the graphs, results in:

Traceback (most recent call last):
  File "/usr/bin/kubuntu-retry-builds", line 90, in <module>
    lp = Launchpad.login_with("kubuntu-retry-builds", "production")
  File "/usr/lib/python3/dist-packages/launchpadlib/launchpad.py", line 549, in login_with
    credential_save_failed, version)
  File "/usr/lib/python3/dist-packages/launchpadlib/launchpad.py", line 352, in _authorize_token_and_login
    authorization_engine.unique_consumer_id)
  File "/usr/lib/python3/dist-packages/launchpadlib/credentials.py", line 337, in load
    return self.do_load(unique_key)
  File "/usr/lib/python3/dist-packages/launchpadlib/credentials.py", line 391, in do_load
    'launchpadlib', unique_key)
  File "/usr/lib/python3/dist-packages/keyring/core.py", line 41, in get_password
    return _keyring_backend.get_password(service_name, username)
  File "/usr/lib/python3/dist-packages/keyring/backends/SecretService.py", line 65, in get_password
    return item.get_secret().decode('utf-8')
  File "/usr/lib/python3/dist-packages/secretstorage/item.py", line 102, in get_secret
    decryptor = Cipher(aes, modes.CBC(aes_iv), default_backend()).decryptor()
  File "/usr/lib/python3/dist-packages/cryptography/hazmat/backends/__init__.py", line 71, in default_backend
    _default_backend = MultiBackend(_available_backends())
  File "/usr/lib/python3/dist...

[Rik Mills (rikmills)]

A proper rebuild of the kad .deb package seemed to fix this.

Initially I missed changing the X-Python3-Version: