[atk] autogen.sh: Add shebang back

[Javier Jardón <jjardon src gnome org>]

commit 6b695fef1a8e8913195acb215801046cfd77e878
Author: Javier Jardón <jjardon gnome org>
Date:   Wed Jan 28 16:28:31 2015 +0000

    autogen.sh: Add shebang back

 autogen.sh |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/autogen.sh b/autogen.sh
index 630e680..91d5034 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -1,3 +1,4 @@
+#!/bin/sh
 # Run this to generate all the initial makefiles, etc.
 
 srcdir=`dirname $0`