Workflow documentation is now in infra-manual

Replace URLs for workflow documentation to appropriate parts of the
OpenStack Project Infrastructure Manual.

Change-Id: Idf519ff362731c106bbd9b63135f8dab4c7b7b92
diff --git a/doc/source/contributing.rst b/doc/source/contributing.rst
index b2a219b..50c0100 100644
--- a/doc/source/contributing.rst
+++ b/doc/source/contributing.rst
@@ -3,9 +3,9 @@
 ============
 
 DevStack uses the standard OpenStack contribution process as outlined in
-`the OpenStack wiki 'How To
-Contribute' <https://wiki.openstack.org/wiki/How_To_Contribute>`__. This
-means that you will need to meet the requirements of the Contributors
+`the OpenStack developer
+guide <http://docs.openstack.org/infra/manual/developers.html>`__. This
+means that you will need to meet the requirements of the Contribututors
 License Agreement (CLA). If you have already done that for another
 OpenStack project you are good to go.