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. Enable this.

Change-Id: I981b05275e1a75e3c42ea3ef24812cded0cefc0d

doc/source/conf.py

@@ -50,6 +50,8 @@ add_module_names = True
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = 'sphinx'
 
+suppress_warnings = ['image.nonlocal_uri']
+
 # -- Options for HTML output --------------------------------------------------
 
 # The theme to use for HTML and HTML Help pages.  Major themes that come with
@@ -70,6 +72,3 @@ latex_documents = [
      u'%s Documentation' % project,
      u'OpenStack Foundation', 'manual'),
 ]
-
-# Example configuration for intersphinx: refer to the Python standard library.
-#intersphinx_mapping = {'http://docs.python.org/': None}

doc/source/contributing.rst

@@ -1 +1,4 @@
-.. include:: ../../CONTRIBUTING.rst
+Contributing
+============
+
+.. include:: ../../CONTRIBUTING.rst

doc/source/index.rst

@@ -11,6 +11,7 @@ Contents:
 
    readme
    installation
+   usage
    command-list
    contributing
 

setup.cfg

@@ -27,9 +27,10 @@ packages =
 
 [build_sphinx]
 builders = html,man
+all-files = 1
+warning-is-error = 1
 source-dir = doc/source
 build-dir = doc/build
-all_files = 1
 
 [upload_sphinx]
 upload-dir = doc/build/html