Update flake8-import-order to 2a595f1

[yufangzhang]

Test starts failing with the error below, which is fixed in 2a595f1
(aka version 0.9 unreleased):

Traceback (most recent call last):
  File "/Users/yufang/.virtualenvs/test/bin/flake8", line 11, in <module>
    sys.exit(main())
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/main/cli.py", line 16, in main
    app.run(argv)
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/main/application.py", line 316, in run
    self._run(argv)
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/main/application.py", line 299, in _run
    self.initialize(argv)
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/main/application.py", line 290, in initialize
    self.register_plugin_options()
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/main/application.py", line 150, in register_plugin_options
    self.check_plugins.register_options(self.option_manager)
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/plugins/manager.py", line 451, in register_options
    list(self.manager.map(register_and_enable))
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/plugins/manager.py", line 261, in map
    yield func(self.plugins[name], *args, **kwargs)
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/plugins/manager.py", line 447, in register_and_enable
    call_register_options(plugin)
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/plugins/manager.py", line 357, in generated_function
    return method(optmanager, *args, **kwargs)
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8/plugins/manager.py", line 207, in register_options
    add_options(optmanager)
  File "/Users/yufang/.virtualenvs/test/lib/python2.7/site-packages/flake8_import_order/flake8_linter.py", line 32, in add_options
    parser.config_options.append("application-import-names")
AttributeError: 'OptionManager' object has no attribute 'config_options'

[yufangzhang]

background info: savoirfairelinux/flake8-copyright#7

[coveralls]

Coverage remained the same at 51.584% when pulling f8fe264 on update_flake8_import_order_version into b24ca77 on master.