Fix: Price by customer: a client must be able to have multiple products

with customer prices

htdocs/product/price.php

@@ -5,6 +5,7 @@
  * Copyright (C) 2005-2013	Regis Houssin			<regis.houssin@capnetworks.com>
  * Copyright (C) 2006		Andre Cianfarani		<acianfa@free.fr>
  * Copyright (C) 2014		Florian Henry			<florian.henry@open-concept.pro>
+ * Copyright (C) 2014		Juanjo Menent			<jmenent@2byte.es>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -820,7 +821,7 @@ if (! empty($conf->global->PRODUIT_CUSTOMER_PRICES)) {
 		print '<tr>';
 		print '<td>' . $langs->trans('ThirdParty') . '</td>';
 		print '<td>';
-		print $form->select_company('', 'socid', 's.rowid NOT IN (SELECT fk_soc FROM ' . MAIN_DB_PREFIX . 'product_customer_price)', 1);
+		print $form->select_company('', 'socid', 's.rowid NOT IN (SELECT fk_soc FROM ' . MAIN_DB_PREFIX . 'product_customer_price WHERE fk_product='.$object->id.')', 1);
 		print '</td>';
 		print '</tr>';