[IMP] o2m: do not display viewmanager header when only one view defined
[IMP] o2m: do not display viewmanager header when only one view defined


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