Description of the issue/feature this PR addresses:
firstname, lastname and lastname2 fields should only be required if
contact `type` is `contact`. In partner_firstname module this is done
right with `('type', '=', 'contact')` leave in attrs required domain.
But in partner_second_last_name there is no such leave, so if the
contact is an address, the fields are mandatory too.
Current behavior:
Either firstname, lastname or lastname2 are mandatory when a contact is
not a company.
Desired behavior after PR is merged:
firstname, lastname or lastname2 are mandatory when the contact is of
type `contact`
Jon Zaballa
Pedro M. Baeza
Jairo Llopis