Stop using published_on in rs to decide whether to download a routerd…

…esc.

The consensus voters shouldn't actually include such old routers in
the consensus anyway, so this logic shouldn't come up...

but if a client _does_ download something it wouldn't use, it won't
retry infinitely: see checks for WRA_NEVER_DOWNLOADABLE.

src/feature/nodelist/networkstatus.c

@@ -2615,15 +2615,12 @@ networkstatus_parse_flavor_name(const char *flavname)
 int
 client_would_use_router(const routerstatus_t *rs, time_t now)
 {
+  (void) now;
   if (!rs->is_flagged_running) {
     /* If we had this router descriptor, we wouldn't even bother using it.
      * (Fetching and storing depends on by we_want_to_fetch_flavor().) */
     return 0;
   }
-  if (rs->published_on + OLD_ROUTER_DESC_MAX_AGE < now) {
-    /* We'd drop it immediately for being too old. */
-    return 0;
-  }
   if (!routerstatus_version_supports_extend2_cells(rs, 1)) {
     /* We'd ignore it because it doesn't support EXTEND2 cells.
      * If we don't know the version, download the descriptor so we can