Change the location of the categories cache

was: /var/db/freshports/cache/general/categories.php
now: /var/db/freshports/cache/html/categories.php

Why?

* cache/general can be cleared at any time - this entity is different
  and is to be always present and replaced only when a new file is
  ready.
* since the new file will be created by the backend (ingress node),
  we put it in cache/html instead.

www/search.php

@@ -1121,7 +1121,7 @@ function WildCardQuery($db, $stype, $Like, $query) {
 
 <?php
 # the goal: have a periodic script which refreshes this file avoiding race conditions, e.g. mv
-define('CATEGORIES_CACHE_LIST', '/var/db/freshports/cache/general/categories.php');
+define('CATEGORIES_CACHE_LIST', '/var/db/freshports/cache/html/categories.php');
 
 if (file_exists(CATEGORIES_CACHE_LIST)) {
  ?>