before this commit: when creating a product from frontend and editing the product and delete image, it doesn't get any url thus generating the traceback. after this commit: if url is not defined then return None from ir.qweb.field.image field converter task-2063293 closes odoo/odoo#40866 X-original-commit: 2efad751e66931fd25a41c1b7d46865bccbc774a Signed-off-by: Jérémy Kersten (jke) <jke@openerp.com>