o Only operate the /var/db IP files via rc.newwanip(v6)
o Consistenly flush a cache IP on a triggered reload
o Remove IPv6 address removal workaround from https://redmine.pfsense.org/issues/2627
o Assume that IP is properly checked making $cacheip != $ip a valid assumption when $cacheip is empty
o Remove creation from dhclient script
".ext" came to be because dhclient-script from BSD is also under sbin/,
but since we always explicity use this one just move it to a neutral
location and point to it.
