[FIX] web: don't print nothing when something is there
[FIX] web: don't print nothing when something is there

In most backend views using CTRL+P to use browser printing would only
print an header without the content.

stumbled-uppon-when-checking: opw-659430 opw-660763

dfang/odoo,microcom/odoo,Elico-Corp/odoo_OCB,ygol/odoo,dfang/odoo,Elico-Corp/odoo_OCB,laslabs/odoo,stephen144/odoo,sysadminmatmoz/OCB,bplancher/odoo,microcom/odoo,ygol/odoo,dfang/odoo,storm-computers/odoo,storm-computers/odoo,hip-odoo/odoo,sysadminmatmoz/OCB,bplancher/odoo,stephen144/odoo,ygol/odoo,sysadminmatmoz/OCB,laslabs/odoo,microcom/odoo,laslabs/odoo,microcom/odoo,ygol/odoo,Elico-Corp/odoo_OCB,stephen144/odoo,hip-odoo/odoo,hip-odoo/odoo,hip-odoo/odoo,storm-computers/odoo,hip-odoo/odoo,bplancher/odoo,stephen144/odoo,Elico-Corp/odoo_OCB,hip-odoo/odoo,bplancher/odoo,Elico-Corp/odoo_OCB,microcom/odoo,dfang/odoo,stephen144/odoo,dfang/odoo,microcom/odoo,sysadminmatmoz/OCB,storm-computers/odoo,ygol/odoo,Elico-Corp/odoo_OCB,storm-computers/odoo,bplancher/odoo,stephen144/odoo,laslabs/odoo,laslabs/odoo,ygol/odoo,bplancher/odoo,sysadminmatmoz/OCB,storm-computers/odoo,laslabs/odoo,dfang/odoo,ygol/odoo,sysadminmatmoz/OCB,sysadminmatmoz/OCB