when our red/recv/recvmsg in imsg_read gives EINTR or EAGAIN, do not

signal "connection closed" upstream.
spotted by Valentin Kozamernik <tin@komna.com>

src/usr.sbin/ntpd/imsg.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: imsg.c,v 1.11 2005/04/26 15:18:22 henning Exp $ */
+/*	$OpenBSD: imsg.c,v 1.12 2007/03/19 10:03:25 henning Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -46,7 +46,7 @@ imsg_read(struct imsgbuf *ibuf)
 			log_warn("imsg_read: pipe read error");
 			return (-1);
 		}
-		return (0);
+		return (-2);
 	}
 
 	ibuf->r.wpos += n;