change test to slider for disk create

app/UI/Disk/Forms/UpdateForm.php

@@ -66,9 +66,9 @@ class UpdateForm extends BaseForm implements ClientArea
         $this->addField(new Hidden("id"));
         //size
         $this->resourceManager = new ResourceManager();
-        $field = new Range('additionalDiskSize', $this->minSize, $this->resourceManager->disk()->free());
+        $field = new Range('additionalDiskSize', 0, $this->resourceManager->disk()->free());
         $field->addValidator(new DiskSizeValidator('additionalDiskSize',true));
-        $field->setDefaultValue($this->minSize);
+        $field->setDefaultValue(0);
         $this->addField($field);
         //backup
         if ($this->configuration()->isPermissionAdditionalDiskBackup())