[validation error] refactor validation error handling so translation is done on the web side Users should now use cubicweb.validation_error helper function that will activate the feature with other handy behaviours. Also test testing for message in errors should call exception.tr(unicode) before comparing. Using bare ValidationError keep backward compat.

sync_schema_props_perms('state_of')
sync_schema_props_perms('transition_of')
for etype in ('State', 'BaseTransition', 'Transition', 'WorkflowTransition'):
    sync_schema_props_perms((etype, 'name', 'String'))