reorder position on folder and category tables before delete action

core/lib/Thelia/Model/Category.php

@@ -106,7 +106,7 @@ class Category extends BaseCategory
     public function preDelete(ConnectionInterface $con = null)
     {
         $this->dispatchEvent(TheliaEvents::BEFORE_DELETECATEGORY, new CategoryEvent($this));
-
+        $this->reorderBeforeDelete();
         return true;
     }
 

core/lib/Thelia/Model/Folder.php

@@ -94,7 +94,7 @@ class Folder extends BaseFolder
     public function preDelete(ConnectionInterface $con = null)
     {
         $this->dispatchEvent(TheliaEvents::BEFORE_DELETEFOLDER, new FolderEvent($this));
-
+        $this->reorderBeforeDelete();
         return true;
     }
 

core/lib/Thelia/Model/Tools/PositionManagementTrait.php

@@ -198,4 +198,11 @@ trait PositionManagementTrait {
             }
         }
     }
+
+    protected function reorderBeforeDelete()
+    {
+        $this->createQuery()
+            ->filterByParent($this->getParent())
+            ->update(array('Position' => '(position-1)'));
+    }
 }