Turn on warning-is-error in doc build

* Fixes warnings in RST file
* Suppress warning log from pyeclib during the doc build.
  pyeclib emits a warning message on an older liberasurecode [1]
  and sphinx treats this as error (when warning-is-error is set).
  There is no need to check warnings during the doc build,
  so we can safely suppress the warning.

This is a part of the doc migration community-wide effort.
http://specs.openstack.org/openstack/docs-specs/specs/pike/os-manuals-migration.html

[1] https://github.com/openstack/pyeclib/commit/d163972b

Change-Id: I9adaee29185a2990cc3985bbe0dd366e22f4f1a2

doc/source/conf.py

@@ -27,10 +27,20 @@
 # serve to show the default.
 
 import datetime
+import logging
 import os
 from swift import __version__
 import sys
 
+# NOTE(amotoki): Our current doc build job uses an older version of
+# liberasurecode which comes from Ubuntu 16.04.
+# pyeclib emits a warning message if liberasurecode <1.3.1 is used [1] and
+# this causes the doc build failure if warning-is-error is enabled in Sphinx.
+# As a workaround we suppress the warning message from pyeclib until we use
+# a newer version of liberasurecode in our doc build job.
+# [1] https://github.com/openstack/pyeclib/commit/d163972b
+logging.getLogger('pyeclib').setLevel(logging.ERROR)
+
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.

setup.cfg

@@ -105,6 +105,7 @@ paste.filter_factory =
 all_files = 1
 build-dir = doc/build
 source-dir = doc/source
+warning-is-error = 1
 
 [egg_info]
 tag_build =