odhcp6c: Timing workaround for buggy servers

git-svn-id: svn://svn.openwrt.org/openwrt@37951 3c298f89-4303-0410-b956-a3cf2f4a3e73
AA: odhcp6c: work around buggy server timeouts

git-svn-id: svn://svn.openwrt.org/openwrt@37952 3c298f89-4303-0410-b956-a3cf2f4a3e73