[-] BO : Fixed default values when add new product (available-date & default id group shop)

classes/stock/StockAvailable.php

@@ -611,6 +611,8 @@ class StockAvailableCore extends ObjectModel
 
 			$group_ok = true;
 		}
+		else
+			$params['id_group_shop'] = 0;
 
 		// if no group specific restriction, set simple shop restriction
 		if (!$group_ok)