[FIX] account: correct `contract_count` value.
[FIX] account: correct `contract_count` value.

Use `child_of` operator to match the search that will be done by the
search view.

alhashash/odoo,stephen144/odoo,ygol/odoo,optima-ict/odoo,alhashash/odoo,mkieszek/odoo,optima-ict/odoo,hip-odoo/odoo,hip-odoo/odoo,bplancher/odoo,syci/OCB,stephen144/odoo,sysadminmatmoz/OCB,mkieszek/odoo,stephen144/odoo,hip-odoo/odoo,microcom/odoo,Elico-Corp/odoo_OCB,bplancher/odoo,laslabs/odoo,hip-odoo/odoo,mkieszek/odoo,sysadminmatmoz/OCB,dfang/odoo,dfang/odoo,bplancher/odoo,ygol/odoo,sysadminmatmoz/OCB,storm-computers/odoo,laslabs/odoo,bplancher/odoo,stephen144/odoo,ygol/odoo,dfang/odoo,sysadminmatmoz/OCB,hip-odoo/odoo,optima-ict/odoo,microcom/odoo,microcom/odoo,storm-computers/odoo,syci/OCB,sysadminmatmoz/OCB,tvtsoft/odoo8,stephen144/odoo,laslabs/odoo,sysadminmatmoz/OCB,storm-computers/odoo,laslabs/odoo,ygol/odoo,optima-ict/odoo,mkieszek/odoo,Elico-Corp/odoo_OCB,dfang/odoo,mkieszek/odoo,sysadminmatmoz/OCB,optima-ict/odoo,mkieszek/odoo,alhashash/odoo,storm-computers/odoo,Elico-Corp/odoo_OCB,ygol/odoo,storm-computers/odoo,optima-ict/odoo,syci/OCB,ygol/odoo,microcom/odoo,Elico-Corp/odoo_OCB,dfang/odoo,storm-computers/odoo,alhashash/odoo,tvtsoft/odoo8,microcom/odoo,tvtsoft/odoo8,tvtsoft/odoo8,tvtsoft/odoo8,alhashash/odoo,syci/OCB,Elico-Corp/odoo_OCB,tvtsoft/odoo8,syci/OCB,ygol/odoo,laslabs/odoo,bplancher/odoo,bplancher/odoo,dfang/odoo,syci/OCB,Elico-Corp/odoo_OCB,alhashash/odoo,microcom/odoo,stephen144/odoo,laslabs/odoo,hip-odoo/odoo