[controller] UndoController: fix output method (closes: #1776091)
Fix buggy direct output in `UndoController.publish()`.
Raise now a ValidationError instead of malformed string
Changes:
* raise ValidationError when an error occured in undo
* use the new message mechanism based on _cwmsgid
If errors are not fatal, you have to change publish() method.
[MESSAGES CONTROL]
disable-msg = C0301
[VARIABLES]
# Enable / disable this checker
enable-variables = yes
additional-builtins = _, display_name
[BASIC]
required-attributes=
attr-rgx = (w|[a-z_][a-z0-9_]{2,30})
variable-rgx = (w|[a-z_][a-z0-9_]{2,30})$
argument-rgx = (w|[a-z_][a-z0-9_]{2,30})$
[TYPECHECK]
generated-members=debug,info,notice,warning,error,critical,exception