[IMP] simplify summing operation (sum builtin was added in 2.3)
[IMP] simplify summing operation (sum builtin was added in 2.3)
MarkusTeufelberger/openobject-server,gisce/openobject-server,ovnicraft/openerp-server,splbio/openobject-server,splbio/openobject-server,gisce/openobject-server,splbio/openobject-server,ovnicraft/openerp-server,MarkusTeufelberger/openobject-server,gisce/openobject-server,vnc-biz/openerp-server,vnc-biz/openerp-server,MarkusTeufelberger/openobject-server