Fix duplication of ConfigFrontend snippets for DefaultBackend
Fix duplication of ConfigFrontend snippets for DefaultBackend

This fixes an issue where any frontend configuration is duplicated twice for the default backend, e.g. config-frontend in the ConfigMap of `http-response add-header my-header` results in two headers `my-header` in the response from the default backend

jcmoraisjr/haproxy-ingress,jcmoraisjr/haproxy-ingress