[FIX] crm: avoid crash when creating activity
[FIX] crm: avoid crash when creating activity

When creating an acitivity generating a calendar event, if
the model is not crm.lead (ex: sale.order), the default_get
will crash since no value for res_model_id is given.

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