bin/61084: nfsd sometimes exits prematurely during port-scan

[Phil Brennan]

The fix for this has not been committed to RELENG_5_2.
src/usr.sbin/nfsd/nfsd.c is still at 1.28, when it should be 1.29.
This is very unfortunate, as it allows a denial of service simply by
running nmap against the box. Could this be committed to this branch
also, as there are quite a lot of people still running 5.2.1.
Thanks. ( Just got bitten by this today )
Regards,

Philip Brennan