Fix the old doc links

Fix the old doc links in CONTRIBUTING.rst
and doc/source/index.rst.

Change-Id: I272742d6c344ea9eb6cb8ab18521049cc7e4a9da

CONTRIBUTING.rst

@@ -1,13 +1,13 @@
 If you would like to contribute to the development of OpenStack,
 you must follow the steps in this page:
 
-   http://docs.openstack.org/infra/manual/developers.html
+   https://docs.openstack.org/infra/manual/developers.html
 
 Once those steps have been completed, changes to OpenStack
 should be submitted for review via the Gerrit tool, following
 the workflow documented at:
 
-   http://docs.openstack.org/infra/manual/developers.html#development-workflow
+   https://docs.openstack.org/infra/manual/developers.html#development-workflow
 
 Pull requests submitted through GitHub will be ignored.
 

doc/source/index.rst

@@ -45,7 +45,7 @@ Release Notes
 .. toctree::
    :maxdepth: 1
 
-   Release Notes <http://docs.openstack.org/releasenotes/python-tackerclient>
+   Release Notes <https://docs.openstack.org/releasenotes/python-tackerclient/>
 
 
 Indices and Tables