util: Fix shebang for python2 scripts

Python 3 is the default Python interpreter on most modern systems.
Python 2 scripts must specify they should be run with Python 2 in their
shebang. Solves issue raised in CB:28953.

Change-Id: I9ace4afd668539c05e7ace30e255af50c7a069c2
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/29666
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

util/ipqheader/mbn_tools.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 #===============================================================================
 #
 # MBN TOOLS