Correct two links.

The github project has changed from `openstack-ci` to `openstack-infra`,
but two links in the documentation do not reflect this change.

Change-Id: I9359d1071f33719da39fdefd14deea728b9dbfff
Reviewed-on: https://review.openstack.org/23033
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins
diff --git a/doc/source/zuul.rst b/doc/source/zuul.rst
index 9fdf04d..3863500 100644
--- a/doc/source/zuul.rst
+++ b/doc/source/zuul.rst
@@ -35,7 +35,7 @@
 The three sections of this config and their options are documented below.
 You can also find an example zuul.conf file in the git
 `repository
-<https://github.com/openstack-ci/zuul/blob/master/etc/zuul.conf-sample>`_
+<https://github.com/openstack-infra/zuul/blob/master/etc/zuul.conf-sample>`_
 
 jenkins
 """""""