ar7-2.4 cleanup

- Switch to generic init scripts (/sbin/mount_root, /bin/firstboot, 
   /etc/preinit), failsafe part moved to /etc/preinit.arch.
   This should fix #1449 with an added benefit of using mini_fo.
 - Switch to generic /etc/config/network.
 - ar7 flashmap: change "OpenWrt" to "rootfs_data", move ar7_mtd_cleanup
   out of .exit.


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@6604 3c298f89-4303-0410-b956-a3cf2f4a3e73

target/linux/ar7-2.4/base-files/default/etc/preinit.arch

@@ -0,0 +1,5 @@
+#!/bin/sh
+[ -z "$FAILSAFE" ] || {
+	echo /bin/true > /proc/sys/kernel/hotplug
+	telnetd -l /bin/login <> /dev/null 2>&1
+}