[FIX] In graph view group by display wrong value. bug-1171937
[FIX] In graph view group by display wrong value. bug-1171937

akretion/openerp-web,akretion/openerp-web,akretion/openerp-web,havt/openerp-web,havt/openerp-web,havt/openerp-web,havt/openerp-web,havt/openerp-web