Events currently have a reply_to field that is purely informative. Indeed
it has to be explicitely taken into account when using mail templates and
is not used for setting classic reply-to of other messages.
This commit removes this field as it is simpler to have a standard
behavior as in all other addons. If a custom reply-to is required it
can be set on the mail template or using the mail composer.
Thibault Delavallée
b1642f8710