Add zuul-sphinx as a requirement

This renames the internal sphinx domain from zuul to zuuldoc.  This
is a temporary measure to avoid colliding with the domain defined
in zuul-sphinx (because of the initial data required, it's not
easy for us to simply add new directives/roles without at least
porting *some* of the framework into zuul-sphinx).

I expect to do that when this has stabilized.

Change-Id: I26be542a6d4f6266f7843ada5939172656b8b847
Depends-On: I8a1534f7c2614ee11411cf228de38931257fc970
diff --git a/doc/source/conf.py b/doc/source/conf.py
index ca9c9b0..fa00593 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -30,13 +30,14 @@
     'sphinx.ext.graphviz',
     'sphinxcontrib.blockdiag',
     'sphinxcontrib.programoutput',
+    'zuul_sphinx',
     'zuul.sphinx.ansible',
     'zuul.sphinx.zuul',
 ]
 #extensions = ['sphinx.ext.intersphinx']
 #intersphinx_mapping = {'python': ('http://docs.python.org/2.7', None)}
 
-primary_domain = 'zuul'
+primary_domain = 'zuuldoc'
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']