[-] Installer : Undefined variable due to hook call in objectModel::add()

git-svn-id: http://dev.prestashop.com/svn/v1/branches/1.5.x@15047 b9a71923-0436-4b27-9f14-aed3839534dd

classes/Hook.php

@@ -269,6 +269,8 @@ class HookCore extends ObjectModel
 			
 			// Get all available payment module
 			$payment_modules = array();
+
+			if (isset($context->shop->id))
 				foreach (Module::getPaymentModules() as $module)
 					$payment_modules[] = $module['name'];