Fix scrutinizer warning

htdocs/categories/class/categorie.class.php

@@ -1478,7 +1478,7 @@ class Categorie extends CommonObject
 			$handle=opendir($dir);
             if (is_resource($handle))
             {
-    			while (($file = readdir($handle)) != false)
+    			while (($file = readdir($handle)) !== false)
     			{
     				if (dol_is_file($dir.$file) && preg_match('/(\.jpg|\.bmp|\.gif|\.png|\.tiff)$/i',$dir.$file))
     				{