This patch adds the ``warning-is-error`` flag in setup.cfg
to build documents and also fix failure with the introduction
of this flag.
Change-Id: I872b6eadae4191a963747636ba356b199b482b2e
The gating on python 3.4 is restricted to <= Mitaka.
This is due to the change from Ubuntu Trusty to Xenial,
where only python3.5 is available.
There is no need to continue to keep these settings.
Change-Id: Idadd9dbf89275cac6dac4cba55abe4ef13a9748a