revert code to 3.0 behavior. Fixes #1616

If there's no 'ipaddr' in the listen section, tell the admin
to set one.  Do NOT invent "ipaddr = *".

src/main/listen.c

@@ -1312,14 +1312,9 @@ int common_socket_parse(CONF_SECTION *cs, rad_listen_t *this)
 	if (rcode != 0) rcode = cf_pair_parse(cs, "ipv6addr",
 					      FR_ITEM_POINTER(PW_TYPE_IPV6_ADDR, &ipaddr), NULL, T_INVALID);
 	if (rcode < 0) return -1;
-	/*
-	 *	Default to IPv4 INADDR_ANY
-	 */
 	if (rcode != 0) {
-		memset(&ipaddr, 0, sizeof(ipaddr));
-		ipaddr.af = INADDR_ANY;
-		ipaddr.prefix = 32;
-		ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_ANY);
+		cf_log_err_cs(cs, "No address specified in listen section");
+		return -1;
 	}
 
 	rcode = cf_pair_parse(cs, "port", FR_ITEM_POINTER(PW_TYPE_SHORT, &sock->my_port), "0", T_BARE_WORD);