Upgrading causes problems on FreeBSD.  Undo my change.
On FreeBSD, there is no group 'root'.  It's called 'wheel' there.
Ubuntu disables root by default, and ships with a rule to allow members of the sudo group to sudo.
FreeBSD only allows members of group wheel to su.  It seems logical to by default allows these users to sudo too.
Merge branch 'fix-freebsd' into cdmaster