Raise error when run "tox -egenconfig"

Raise error when run "tox -egenconfig", detail:

genconfig develop-inst-noop: /root/ceilometer
genconfig runtests: PYTHONHASHSEED='2887780094'
genconfig runtests: commands[0] | oslo-config-generator --output-file etc/ceilometer/ceilometer.conf --namespace ceilometer --namespace oslo.concurrency --namespace oslo.db --namespace oslo.messaging --namespace oslo.policy --namespace keystonemiddleware.auth_token
Traceback (most recent call last):
  File ".tox/genconfig/bin/oslo-config-generator", line 11, in <module>
    sys.exit(main())
  File "/root/ceilometer/.tox/genconfig/local/lib/python2.7/site-packages/oslo_config/generator.py", line 256, in main
    generate(conf)
  File "/root/ceilometer/.tox/genconfig/local/lib/python2.7/site-packages/oslo_config/generator.py", line 226, in generate
    for namespace, listing in _list_opts(conf.namespace):
  File "/root/ceilometer/.tox/genconfig/local/lib/python2.7/site-packages/oslo_config/generator.py", line 201, in _list_opts
    invoke_on_load=True)
  File "/root/ceilometer/.tox/genconfig/local/lib/python2.7/site-packages/stevedore/named.py", line 55, in __init__
    verify_requirements)
  File "/root/ceilometer/.tox/genconfig/local/lib/python2.7/site-packages/stevedore/extension.py", line 170, in _load_plugins
    self._on_load_failure_callback(self, ep, err)
  File "/root/ceilometer/.tox/genconfig/local/lib/python2.7/site-packages/stevedore/extension.py", line 162, in _load_plugins
    verify_requirements,
  File "/root/ceilometer/.tox/genconfig/local/lib/python2.7/site-packages/stevedore/named.py", line 123, in _load_one_plugin
    verify_requirements,
  File "/root/ceilometer/.tox/genconfig/local/lib/python2.7/site-packages/stevedore/extension.py", line 187, in _load_one_plugin
    obj = plugin(*invoke_args, **invoke_kwds)
  File "/root/ceilometer/ceilometer/opts.py", line 107, in list_opts
    ceilometer.cmd.alarm.OPTS)),
AttributeError: 'module' object has no attribute 'OPTS'
ERROR: InvocationError: '/root/ceilometer/.tox/genconfig/bin/oslo-config-generator --output-file etc/ceilometer/ceilometer.conf --namespace ceilometer --namespace oslo.concurrency --namespace oslo.db --namespace oslo.messaging --namespace oslo.policy --namespace keystonemiddleware.auth_token'
_______________________________________________________________ summary _______________________________________________________________
ERROR: genconfig: commands failed