loxi-prep: change parse_header to return a tuple
diff --git a/tools/munger/scripts/message_gen.py b/tools/munger/scripts/message_gen.py
index b59c42e..6565bb8 100644
--- a/tools/munger/scripts/message_gen.py
+++ b/tools/munger/scripts/message_gen.py
@@ -961,14 +961,10 @@
     an ofp_header Python class.
 
     @param binary_string The packet (string) to be parsed
-    @param raw If true, interpret the packet as an L2 packet.  Not
-    yet supported.
-    @return An ofp_header object
+    @return Tuple of (verison, type, length, xid)
 
     \"""
-    hdr = ofp_header()
-    hdr.unpack(binary_string)
-    return hdr
+    return struct.unpack_from("!BBHL", binary_string)
 
 """