Use Sphinx 1.5 warning-is-error

With pbr 2.0 and Sphinx 1.5, the setting for treat sphinx warnings as
errors is setting warning-is-error in build_sphinx section. Migrate
the setting from the old warnerrors one.

The history document is removed because some of the commit messages used
in ChangeLog were being identified as invalid markup and there doesn't
appear to be anyway to edit there retroactively nor disable warnings on
a specific file.

Change-Id: I79e7ac56d5af1151865686761f3d40a11efbf472

doc/source/history.rst

@@ -1 +0,0 @@
-.. include:: ../../ChangeLog

doc/source/index.rst

@@ -31,14 +31,6 @@ Contents
    FAQ
    contributing
 
-Release Notes
-=============
-
-.. toctree::
-   :maxdepth: 1
-
-   history
-
 Indices and tables
 ==================
 

setup.cfg

@@ -81,9 +81,10 @@ oslo.config.opts =
     oslo.messaging = oslo_messaging.opts:list_opts
 
 [build_sphinx]
+warning-is-error = 1
+all-files = 1
 source-dir = doc/source
 build-dir = doc/build
-all_files = 1
 
 [upload_sphinx]
 upload-dir = doc/build/html
@@ -101,6 +102,3 @@ input_file = oslo_messaging/locale/oslo_messaging.pot
 keywords = _ gettext ngettext l_ lazy_gettext
 mapping_file = babel.cfg
 output_file = oslo_messaging/locale/oslo_messaging.pot
-
-[pbr]
-warnerrors = true