[FIX] point_of_sale: display traceback

Since ffda023295, the error is not 'OpenERP Server Error' but 'Odoo Server
Error'.
In case we change of name once again, check based on the name

Avoid "traceback not available" error in PoS when there is a traceback.

addons/point_of_sale/static/src/js/chrome.js

@@ -612,7 +612,7 @@ var Chrome = PosBaseWidget.extend({
         if(err.message === 'XmlHttpRequestError '){
             title = 'Network Failure (XmlHttpRequestError)';
             body  = 'The Point of Sale could not be loaded due to a network problem.\n Please check your internet connection.';
-        }else if(err.message === 'OpenERP Server Error'){
+        }else if(err.code === 200){
             title = err.data.message;
             body  = err.data.debug;
         }