Fix the invalid links in docs

The url links are invalid or not found in these docs.
Replace them with the right ones according to the lastest OpenStack
websites.

Change-Id: I5e3a254229548af6aa2e53da4e0125cfe47193b9
diff --git a/doc/source/index.rst b/doc/source/index.rst
index b7053a1..ac57e68 100644
--- a/doc/source/index.rst
+++ b/doc/source/index.rst
@@ -286,6 +286,6 @@
            pass
 
 
-.. _Tempest Docs: http://docs.openstack.org/developer/tempest/
-.. _Tempest HACKING: http://docs.openstack.org/developer/tempest/HACKING.html
-.. _Tempest Plugins: http://docs.openstack.org/developer/tempest/plugin.html
+.. _Tempest Docs: https://docs.openstack.org/tempest/latest/
+.. _Tempest HACKING: https://docs.openstack.org/tempest/latest/HACKING.html
+.. _Tempest Plugins: https://docs.openstack.org/tempest/latest/plugin.html