Switch from oslosphinx to openstackdocstheme

As part of the docs migration work[0] for Pike we need to switch to use
the openstackdocstheme.

Fix one display problem with wrong section markup in the index file.

[0]https://review.openstack.org/#/c/472275/

Change-Id: Ide31218a7f37ba5d959de99cab48fc6513bf426f

releasenotes/source/conf.py

@@ -45,8 +45,8 @@ from swift import __version__
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = [
-    'oslosphinx',
     'reno.sphinxext',
+    'openstackdocstheme',
 ]
 
 # Add any paths that contain templates here, relative to this directory.
@@ -135,8 +135,7 @@ pygments_style = 'sphinx'
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-#
-html_theme = 'default'
+html_theme = 'openstackdocs'
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
@@ -178,11 +177,10 @@ html_theme = 'default'
 #
 # html_extra_path = []
 
-# If not None, a 'Last updated on:' timestamp is inserted at every page
-# bottom, using the given strftime format.
-# The empty string is equivalent to '%b %d, %Y'.
-#
-# html_last_updated_fmt = None
+# If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
+# using the given strftime format.
+# html_last_updated_fmt = '%b %d, %Y'
+html_last_updated_fmt = '%Y-%m-%d %H:%M'
 
 # If true, SmartyPants will be used to convert quotes and dashes to
 # typographically correct entities.
@@ -355,3 +353,8 @@ htmlhelp_basename = 'SwiftReleaseNotesdoc'
 # texinfo_no_detailmenu = False
 
 locale_dirs = ['locale/']
+
+# -- Options for openstackdocstheme -------------------------------------------
+repository_name = 'openstack/swift'
+bug_project = 'swift'
+bug_tag = ''