Updated openstack/openstack
Project: openstack/taskflow  dcd18dbf498e444a025468a6606418a77e63cefe

Format failures via a static method

To allow for customized formatting of failures create and
use a tiny helper function that can be used to alter how
failures are formatted to better suite the users needs.

This allows for users to dervive from the top level class and
adjust there formatting for how they see fit (as long as they
return the same two values that the methods api defines).

Change-Id: Ib91bd28ff4f24d831bb97715282ee8f3b6050c4c