fix to util_sock.c

[Andrew Tridgell]

> We actually used to use this instead of read() on sockets,
> but one of the earlier versions of Solaris I recall has a
> horrible bug in recv which causes this to fail. I think
> FreeBSD at some point had a problem with this also.

yep, we switched to recv() in the head branch in May 99 and found that
recv() is completely broken on Solaris 2.5. We switched back in
November 99. 

Cheers, Tridge