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

classes/Product.php

@@ -169,7 +169,7 @@ class ProductCore extends ObjectModel
 	public $available_for_order = 1;
 
 	/** @var string Object available order date */
-	public $available_date;
+	public $available_date = '0000-00-00';
 
 	/** @var enum Product condition (new, used, refurbished) */
 	public $condition;

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)