Removed openshift deployment infos (v2 has been sunset)

docs/advanced_topics/deploying.rst

@@ -8,11 +8,6 @@ Wagtail is straightforward to deploy on modern Linux-based distributions, but se
 
 Our current preferences are for Nginx, Gunicorn and supervisor on Debian, but Wagtail should run with any of the combinations detailed in Django's `deployment documentation <https://docs.djangoproject.com/en/dev/howto/deployment/>`_.
 
-On Openshift
-~~~~~~~~~~~~
-
-`OpenShift <https://www.openshift.com/>`_ is Red Hat's Platform-as-a-Service (PaaS) that allows developers to quickly develop, host, and scale applications in a cloud environment. With their Python, PostgreSQL and Elasticsearch cartridges there's all you need to host a Wagtail site. To get quickly up and running you may use the `wagtail-openshift-quickstart <https://github.com/texperience/wagtail-openshift-quickstart>`_.
-
 On other PAASs and IAASs
 ~~~~~~~~~~~~~~~~~~~~~~~~