removed an irrelevant cast to off_t in the offset wraparound check.

the expression in question is already of type isc_offset_t, which
is just a typedef for off_t.

lib/dns/journal.c

@@ -1275,8 +1275,8 @@ journal_next(dns_journal_t *j, journal_pos_t *pos) {
 	 * Check for offset wraparound.
 	 */
 	if (xhdr.size + sizeof(journal_rawxhdr_t) > ISC_OFFSET_MAXIMUM ||
-	    (off_t)(ISC_OFFSET_MAXIMUM - xhdr.size - sizeof(journal_rawxhdr_t))
-		    < pos->offset) {
+	    ISC_OFFSET_MAXIMUM - xhdr.size - sizeof(journal_rawxhdr_t)
+	    < pos->offset) {
 		isc_log_write(JOURNAL_COMMON_LOGARGS, ISC_LOG_ERROR,
 			      "%s: offset too large", j->filename);
 		return (ISC_R_UNEXPECTED);