Make ft_pageLookup respect the namespace restriction again

Before this change all pages of the given namespace have been included
in the result, now the search is restricted to the namespace again as it
was before the new indexer has been implemented.

inc/fulltext.php

@@ -241,11 +241,11 @@ function _ft_pageLookup(&$data){
             }
         }
     }
+
     if (isset($ns)) {
-        foreach ($page_idx as $p_id) {
-            if (strpos($p_id, $ns) === 0) {
-                if (!isset($pages[$p_id]))
-                    $pages[$p_id] = p_get_first_heading($p_id, false);
+        foreach (array_keys($pages) as $p_id) {
+            if (strpos($p_id, $ns) !== 0) {
+                unset($pages[$p_id]);
             }
         }
     }