Fix broken function prototype

Fixes this error:

PHP Fatal error:  Declaration of Horde_Themes_Css_Cache_Horde_Cache::process() must be compatible
with that of Horde_Themes_Css_Cache::process()
in /datastore/DEVEL/framework/Core/lib/Horde/Themes/Css/Cache/HordeCache.php on line 25

Signed-off-by: Jan Schneider <jan@horde.org>
Bug: 13014

framework/Core/lib/Horde/Themes/Css/Cache/HordeCache.php

@@ -25,7 +25,7 @@ class Horde_Themes_Css_Cache_HordeCache extends Horde_Themes_Css_Cache
 {
     /**
      */
-    public function process($css)
+    public function process($css, $cacheid)
     {
         global $injector;