- fix DUID calculation for virtual interfaces like pppoe-wan (#9503)
- add a config option "duid" to allow users to override the DUID
- use service_kill to cleanly terminate dhcp6c
- bump package revision
git-svn-id: svn://svn.openwrt.org/openwrt/packages@27140 3c298f89-4303-0410-b956-a3cf2f4a3e73