blocklist: blacklist: Chase recent upstream changes

Upstream introduced a fix that avoids blocklistd(8) from running into an
endless loop when it tries to delete an address from the database which
has been added multiple times.

Apply the same fix to blacklistd(8).

Upstream PR:	https://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=57193
MFC after:	2 days

contrib/blocklist/bin/blacklistd.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: blocklistd.c,v 1.11 2025/10/25 16:55:23 christos Exp $	*/
+/*	$NetBSD: blocklistd.c,v 1.12 2025/10/25 18:43:51 christos Exp $	*/
 
 /*-
  * Copyright (c) 2015 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
 #ifdef HAVE_SYS_CDEFS_H
 #include <sys/cdefs.h>
 #endif
-__RCSID("$NetBSD: blocklistd.c,v 1.11 2025/10/25 16:55:23 christos Exp $");
+__RCSID("$NetBSD: blocklistd.c,v 1.12 2025/10/25 18:43:51 christos Exp $");
 
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -329,8 +329,8 @@ update(void)
 			(*lfun)(LOG_INFO, "released %s/%d:%d after %d seconds",
 			    buf, c.c_lmask, c.c_port, c.c_duration);
 		}
-		state_del(state, &c);
-		goto again;
+		if (state_del(state, &c) == 0)
+			goto again;
 	}
 }