Import of opts broken

changing mode of build/scripts-2.7/manila-share from 664 to 775
oslo-config-generator --config-file etc/oslo-config-generator/manila.conf \
 --output-file etc/manila/manila.conf
Traceback (most recent call last):
  File "/usr/bin/oslo-config-generator", line 10, in <module>
    sys.exit(main())
  File "/usr/lib/python2.7/dist-packages/oslo_config/generator.py", line 332, in main
    generate(conf)
  File "/usr/lib/python2.7/dist-packages/oslo_config/generator.py", line 302, in generate
    for namespace, listing in _list_opts(conf.namespace):
  File "/usr/lib/python2.7/dist-packages/oslo_config/generator.py", line 277, in _list_opts
    invoke_on_load=True)
  File "/usr/lib/python2.7/dist-packages/stevedore/named.py", line 55, in __init__
    verify_requirements)
  File "/usr/lib/python2.7/dist-packages/stevedore/extension.py", line 170, in _load_plugins
    self._on_load_failure_callback(self, ep, err)
  File "/usr/lib/python2.7/dist-packages/stevedore/extension.py", line 162, in _load_plugins
    verify_requirements,
  File "/usr/lib/python2.7/dist-packages/stevedore/named.py", line 123, in _load_one_plugin
    verify_requirements,
  File "/usr/lib/python2.7/dist-packages/stevedore/extension.py", line 178, in _load_one_plugin
    plugin = ep.load(require=verify_requirements)
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2312, in load
    return self.resolve()
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2318, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/usr/lib/python2.7/dist-packages/oslo_messaging/opts.py", line 24, in <module>
    from oslo.messaging._drivers import base as drivers_base
ImportError: cannot import name base