[package] iptables: don't use /bin/bash in autogen.sh, breaks FreeBSD. Also move autogen.sh invocation to Build/Configure

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@23369 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/iptables/patches/100-bash-location.patch

@@ -0,0 +1,16 @@
+--- a/autogen.sh
++++ b/autogen.sh
+@@ -1,4 +1,4 @@
+-#!/bin/bash
++#!/usr/bin/env bash
+ 
+ autoreconf -fi;
+ rm -Rf autom4te*.cache;
+--- a/iptables-apply
++++ b/iptables-apply
+@@ -1,4 +1,4 @@
+-#!/bin/bash
++#!/usr/bin/env bash
+ #
+ # iptables-apply -- a safer way to update iptables remotely
+ #