build_sphinx always failed

[Jianghua Wang]

Sphinx1.6.1 was released on 2017-05-16.
https://pypi.python.org/pypi/Sphinx

Since then the jenkins job of gate-os-traits-docs-ubuntu-xenial always fail.

http://logs.openstack.org/49/463649/3/check/gate-os-traits-docs-ubuntu-xenial/d049e47/

2017-05-18 23:38:37.380085 | Exception occurred:
2017-05-18 23:38:37.381718 | File "/home/jenkins/workspace/gate-os-traits-docs-ubuntu-xenial/.tox/venv/local/lib/python2.7/site-packages/sphinx/themes/basic/../basic/layout.html", line 108, in template
2017-05-18 23:38:37.381765 | {%- for css in css_files %}
2017-05-18 23:38:37.381793 | TypeError: 'NoneType' object is not iterable

It looks like a bug with Sphinx 1.6.1. May exclude this version from testing requirements to fix this issue.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/466133

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/466133
Committed: https://git.openstack.org/cgit/openstack/os-traits/commit/?id=fbbe466c7714e69161a859b5bcc12f0ff19ef205
Submitter: Jenkins
Branch: master

commit fbbe466c7714e69161a859b5bcc12f0ff19ef205
Author: jianghua wang <email address hidden>
Date: Fri May 19 01:39:07 2017 +0100

    Build_sphinx always failed.

    Sphinx1.6.1 was released on 2017-05-16.
    https://pypi.python.org/pypi/Sphinx
    Since then the jenkins job of gate-os-traits-docs-ubuntu-xenial
    always failed.

    Let's exclude this Sphinx version to fix the failure.

    Change-Id: Ic7c1bf8f743c6c08897eb6b9a4bbae4a20d61fcc
    Closes-bug: 1691887

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/os-traits 0.3.1 release.