leave: we should also cache time zone

MFC after:	1 week

usr.bin/leave/leave.c

@@ -63,6 +63,7 @@ main(int argc, char **argv)
 	if (setlocale(LC_TIME, "") == NULL)
 		warn("setlocale");
 
+	caph_cache_tzdata();
 	caph_cache_catpages();
 	if (caph_limit_stdio() < 0 || caph_enter() < 0)
 		err(EXIT_FAILURE, "capsicum");