Now rss link in head will update correctly with changes to the config

.themes/classic/source/_includes/head.html

@@ -27,7 +27,8 @@
   <script src="{{ root_url }}/javascripts/octopress.js" type="text/javascript"></script>
   <link href='http://fonts.googleapis.com/css?family=PT+Serif:regular,italic,bold,bolditalic' rel='stylesheet' type='text/css'>
   <link href='http://fonts.googleapis.com/css?family=PT+Sans:regular,italic,bold,bolditalic' rel='stylesheet' type='text/css'>
-  <link href="{{ root_url }}/atom.xml" rel="alternate" title="{{site.title}}" type="application/atom+xml"/>
+  {% capture rss_url %}{% if site.subscribe_rss contains ':' %}{{ site.subscribe_rss }}{% else %}{{ root_url }}{{ site.subscribe_rss }}{% endif %}{% endcapture %}
+  <link href="{{ rss_url }}" rel="alternate" title="{{site.title}}" type="application/atom+xml"/>
   {% include google_analytics.html %}
   {% include google_plus_one.html %}
   {% include twitter_sharing.html %}