CORD-2272: Drop deprecated header.py file

Change-Id: I27f63d3b4cf272f322c60a64f485432cbd919406
diff --git a/xos/models/header.py b/xos/models/header.py
deleted file mode 120000
index 721b5c0..0000000
--- a/xos/models/header.py
+++ /dev/null
@@ -1 +0,0 @@
-attic/header.py
\ No newline at end of file