update the url to the latest one used in the manager

FIX for FS#2463 <https://bugs.dokuwiki.org/index.php?do=details&task_id=2463>

lib/plugins/plugin/classes/ap_manage.class.php

@@ -141,9 +141,18 @@ class ap_manage {
                 break;
 
             case 'update' :
+                $url = $data[0];
                 $date = date('r');
-                if (!$fp = @fopen($file, 'a')) return;
-                fwrite($fp, "updated=$date\n");
+                if (!$fp = @fopen($file, 'r+')) return;
+                $buffer = "";
+                while (($line = fgets($fp)) !== false) {
+                    $urlFound = strpos($line,"url");
+                    if($urlFound !== false) $line="url=$url\n";
+                    $buffer .= $line;
+                }
+                $buffer .= "updated=$date\n";
+                fseek($fp, 0);
+                fwrite($fp, $buffer);
                 fclose($fp);
                 break;
         }