[FIX] correctly check for o2m listview validity
[FIX] correctly check for o2m listview validity

if an edition has been canceled, don't check the form's content as it
does not matter.


havt/openerp-web,havt/openerp-web,akretion/openerp-web,akretion/openerp-web,akretion/openerp-web,havt/openerp-web,havt/openerp-web,havt/openerp-web