[FIX] base: in partner search view, use operator=child_of instead of...

[FIX] base: in partner search view, use operator=child_of instead of filter_domain with a child_of domain

operator child_of has the advantage to do exact ID matching for many2one, and not just matching on the name

bzr revid: dle@openerp.com-20140422150736-o2t3eank6yqttlel