Purpose
=======
Allow to use the following domain in views
```
[('properties', '=', [])]
```
To be able to show / hide elements based on the fact that the
properties is empty or not.
Task-3213639
closes odoo/odoo#115990
X-original-commit: 4c41108df23a1bbce8c5f6918ead80568a72d4ce
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>
Signed-off-by: Stéphane Debauche (std) <std@odoo.com>