[FIX] account: correctly set the opening amount of a bank statement
[FIX] account: correctly set the opening amount of a bank statement

_default_opening_balance is used as a default for the balance_start
field. A default function should return the default value, not attempt
to set it on self, which is what was being done when
_set_opening_balance gets called.

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