[IMP] mail: remove duplicated logs when scheduling activities
[IMP] mail: remove duplicated logs when scheduling activities

Currently when scheduling activities, duplicate logs are created. Indeed
a message is posted when scheduling an activity, editing it and marking it
as done. This leads to a lot of noise being created on records.

This commit remove logs when scheduling and updating an activity. A sole
message is posted when the activity is marked as done.

This is a partial backport of commit 26940f8de4e8c2b8fb71d22fd53f2c537028ac1a targetting saas-15.

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo