incorrect ImportError message raised

Logs show:

2018-03-05 20:50:01.665 35 WARNING stevedore.named [-] Could not load uuid
2018-03-05 20:50:01.666 35 CRITICAL keystone [-] Unhandled error: ImportError: (u'Unable to find %(name)r driver in %(namespace)r.',
 {'namespace': 'keystone.token.provider', 'name': 'uuid'})
2018-03-05 20:50:01.666 35 ERROR keystone Traceback (most recent call last):
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/bin/keystone-manage", line 10, in <module>
2018-03-05 20:50:01.666 35 ERROR keystone sys.exit(main())
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/cmd/manage.py", line 45,
in main
2018-03-05 20:50:01.666 35 ERROR keystone cli.main(argv=sys.argv, config_files=config_files)
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/cmd/cli.py", line 1349, i
n main
2018-03-05 20:50:01.666 35 ERROR keystone CONF.command.cmd_class.main()
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/cmd/cli.py", line 397, in
 main
2018-03-05 20:50:01.666 35 ERROR keystone klass = cls()
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/cmd/cli.py", line 66, in
__init__
2018-03-05 20:50:01.666 35 ERROR keystone self.load_backends()
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/cmd/cli.py", line 129, in
 load_backends
2018-03-05 20:50:01.666 35 ERROR keystone drivers = backends.load_backends()
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/server/backends.py", line
 53, in load_backends
2018-03-05 20:50:01.666 35 ERROR keystone drivers = {d._provides_api: d() for d in managers}
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/server/backends.py", line
 53, in <dictcomp>
2018-03-05 20:50:01.666 35 ERROR keystone drivers = {d._provides_api: d() for d in managers}
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/token/provider.py", line
65, in __init__
2018-03-05 20:50:01.666 35 ERROR keystone super(Manager, self).__init__(CONF.token.provider)
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/common/manager.py", line
181, in __init__
2018-03-05 20:50:01.666 35 ERROR keystone self.driver = load_driver(self.driver_namespace, driver_name)
2018-03-05 20:50:01.666 35 ERROR keystone File "/var/lib/kolla/venv/lib/python2.7/site-packages/keystone/common/manager.py", line
81, in load_driver
2018-03-05 20:50:01.666 35 ERROR keystone raise ImportError(msg, {'name': driver_name, 'namespace': namespace})
2018-03-05 20:50:01.666 35 ERROR keystone ImportError: (u'Unable to find %(name)r driver in %(namespace)r.', {'namespace': 'keystone
.token.provider', 'name': 'uuid'})
2018-03-05 20:50:01.666 35 ERROR keystone

which is misleading. The correct error should be:

2018-03-05 20:50:25.517 47 ERROR keystone ImportError: Unable to find 'uuid' driver in 'keystone.token.provider'.