AttributeError: type object 'str' has no attribute 'format_defaults'

[Davanum Srinivas (DIMS)]

Ceilometer fails with latest oslo.config

Traceback (most recent call last):
  File ".tox/py34/bin/oslo-config-generator", line 10, in <module>
    sys.exit(main())
  File "/home/travis/build/dims/ceilometer/.tox/py34/src/oslo.config/oslo_config/generator.py", line 258, in main
    generate(conf)
  File "/home/travis/build/dims/ceilometer/.tox/py34/src/oslo.config/oslo_config/generator.py", line 248, in generate
    _output_opts(formatter, group, namespaces)
  File "/home/travis/build/dims/ceilometer/.tox/py34/src/oslo.config/oslo_config/generator.py", line 228, in _output_opts
    f.format(opt)
  File "/home/travis/build/dims/ceilometer/.tox/py34/src/oslo.config/oslo_config/generator.py", line 156, in format
    defaults = opt.type.format_defaults(opt.default, opt.sample_default)
AttributeError: type object 'str' has no attribute 'format_defaults'
ERROR: InvocationError: '/home/travis/build/dims/ceilometer/.tox/py34/bin/oslo-config-generator --config-file=etc/ceilometer/ceilometer-config-generator.conf'

[Haïkel Guémar (hguemar)]

Ok, this is also hitting RDO master packages too, so far identified affected components:
* ceilometer
http://trunk.rdoproject.org/centos7/c1/48/c14856a50d9a0c16e43abd79bdb2d82c7a24edfb_18968d75/rpmbuild.log
* manila
http://trunk.rdoproject.org/centos7/bd/81/bd81350547b369d60985450e14404d1647bdbea4_e82cce94/rpmbuild.log
* sahara
http://trunk.rdoproject.org/centos7/85/ac/85ac32e8d30191fce9cba2d5ba5099e21da66cff_2efeaf46/rpmbuild.log