[FIX] packaging: redhat: don't write the conf file if already there
[FIX] packaging: redhat: don't write the conf file if already there

this avoid to overwrite the configuration file at each update.

closes  #11722

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