[fix] problem with context handling in on_change when there is no context
[fix] problem with context handling in on_change when there is no context

gisce/openerp-web,vnc-biz/openerp-web,splbio/openerp-web,MarkusTeufelberger/openerp-web,vnc-biz/openerp-web,vnc-biz/openerp-web,splbio/openerp-web,gisce/openerp-web,MarkusTeufelberger/openerp-web,gisce/openerp-web,MarkusTeufelberger/openerp-web,vnc-biz/openerp-web,splbio/openerp-web