Milter-greylist

Hello,

I found a problem with MX synchronization from a Linux box towards a Tru64 UNIX system.
When the milter-greylist is stopped on Tru64, the MX socket goes to CLOSE_WAIT state
on the Linux system. There the sync_send() goes into an infinite loop, since it does
not check the EOF status on the stream.

I attach a patch which fixes that problem.

This problem may exists towards other platform than Tru64.

Bests,
Attila