Use layout: null instead of none to fix Jekyll warning

mitio · mitio · commit 30057cee4639 · 2015-09-17T14:06:03.000+02:00
"Build Warning: Layout 'none' requested in feed.xml does not exist."
diff --git a/feed.xml b/feed.xml
@@ -1,5 +1,5 @@
 ---
-layout: none
+layout: null
 ---
 <?xml version="1.0" encoding="UTF-8"?>
 <rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
