nfsd won't start on post r243965 kernels without INET6

Just fyi, r243965 introduced a minor pola violation where the
nfsd daemon won't start for kernels built without "options INET6".

The attached patch, which I will commit to head later to-day, fixes
the problem. (Or you can add "options INET6" to your kernel config.)

Reported and tested by avg_at_.

rick