Currently if get_formview_id does not return a specific view id the
mail/view controller produces an url with view_id=False. Due to some
unknown reason it is not taken into account as False but as the
string False since some time. It generates a traceback and prevent
people from using the mail/view controller.
While finding why it seems to have changed we can avoid the issue by
setting the view_id only if set. It has no impact on the redirection
has the default for view is loaded as intended.
Thibault Delavallée
446d4127d9