[FIX] web_forum: fix the comparison of tags ids
[FIX] web_forum: fix the comparison of tags ids

When checking if tags had changed, a missing .ids made it that a recordset was
compared to a set of ids (integers).
As a result, to make an edit the forum would always check that the user had
sufficent karma to retag, even if it was not needed.

opw 1866019

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