bugfix unlimited backup files fails

v2/models/AbstractVm.php

@@ -278,7 +278,9 @@ abstract class AbstractVm extends AbstractObject implements \MGProvision\Proxmox
         $data['storage']  = $storage;
         $data['remove']   = $routing;
         if(is_numeric($maxFiles)){
-            $data['maxfiles'] = (int) $maxFiles;
+            if($maxFiles > 0){
+                $data['maxfiles'] = (int) $maxFiles;
+            }
         }
         if ($compress)
             $data['compress'] = $compress;