doc: Switch from oslosphinx to openstackdocstheme

Per the manuals migration effort, switch to openstackdocstheme [1]

[1] https://specs.openstack.org/openstack/docs-specs/specs/pike/os-manuals-migration.html

Change-Id: I0463f7d39bd72f1d27cfe3f6d5395608b9ed6b29
diff --git a/doc/source/conf.py b/doc/source/conf.py
index 6e3ec02..780237f 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -26,7 +26,13 @@
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = [ 'oslosphinx', 'sphinxcontrib.blockdiag', 'sphinxcontrib.nwdiag' ]
+extensions = [ 'openstackdocstheme', 'sphinxcontrib.blockdiag', 'sphinxcontrib.nwdiag' ]
+
+# openstackdocstheme options
+repository_name = 'openstack-dev/devstack'
+bug_project = 'devstack'
+bug_tag = ''
+html_last_updated_fmt = '%Y-%m-%d %H:%M'
 
 todo_include_todos = True
 
@@ -87,7 +93,7 @@
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'nature'
+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
diff --git a/tox.ini b/tox.ini
index cc7c544..46b15f4 100644
--- a/tox.ini
+++ b/tox.ini
@@ -37,9 +37,9 @@
 deps =
    Pygments
    docutils
-   sphinx>=1.5.1,<1.6.1
+   sphinx>=1.6.2
    pbr>=2.0.0,!=2.1.0
-   oslosphinx
+   openstackdocstheme>=1.11.0
    nwdiag
    blockdiag
    sphinxcontrib-blockdiag
@@ -53,8 +53,8 @@
 [testenv:venv]
 deps =
    pbr>=2.0.0,!=2.1.0
-   sphinx>=1.5.1,<1.6.1
-   oslosphinx
+   sphinx>=1.6.2
+   openstackdocstheme>=1.11.0
    blockdiag
    sphinxcontrib-blockdiag
    sphinxcontrib-nwdiag