[FIX] base: fix SignedIntConverter weight
[FIX] base: fix SignedIntConverter weight

This allow to keep route with an SignedIntConverter with more
priority than a StringConverter.

The default wight is 100, so force the weight to 50 (default intConverter)
was also a fix. But we decide to rewrite the SignedIntConverter based on the
intConverter of WerkZeug.

So now, a controller '/module/<string:xmlid>', will be matched after
'/module/<int:id>". (Same behaviour that before the commit 800ae13712e0e986f690f29ed3940410b5a750d5)

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