Add ipv6 up/down using route (#2372)

SVN-Revision: 8794

package/ppp/files/etc/ppp/ipv6-down

@@ -0,0 +1,2 @@
+#!/bin/sh
+route -A inet6 del $4 dev $1

package/ppp/files/etc/ppp/ipv6-up

@@ -0,0 +1,2 @@
+#!/bin/sh
+route -A inet6 add default $4 dev $1