ipv6-support: Remove unnecessary code

git-svn-id: svn://svn.openwrt.org/openwrt@34957 3c298f89-4303-0410-b956-a3cf2f4a3e73
6relayd: Detect changes of default routes for RAs

git-svn-id: svn://svn.openwrt.org/openwrt@34958 3c298f89-4303-0410-b956-a3cf2f4a3e73