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

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