Configuration: removed "reschedule_timeout" option.

It's not used since cbcd76704c90.

This option is a leftover from previous IPC between router and applications
processes.  It was never documented, though.

Thanks to 洪志道 (Hong Zhi Dao).

src/nxt_conf_validation.c

@@ -496,12 +496,6 @@ static nxt_conf_vldt_object_t  nxt_conf_vldt_app_limits_members[] = {
       NULL,
       NULL },
 
-    { nxt_string("reschedule_timeout"),
-      NXT_CONF_VLDT_INTEGER,
-      0,
-      NULL,
-      NULL },
-
     { nxt_string("requests"),
       NXT_CONF_VLDT_INTEGER,
       0,