Fix to refer invalid memory access on helpers.go
Fix to refer invalid memory access on helpers.go

toophy/xorm,ymhhh/xorm,Michael2008S/xorm,zj8487/xorm,henrylee2cn/xorm,henrylee2cn/xorm,aviau/xorm,vCaesar/xorm,tempbottle/xorm,go-xorm/xorm,evalphobia/xorm,ymhhh/xorm,tempbottle/xorm,go-xorm/xorm,evalphobia/xorm,Michael2008S/xorm,zj8487/xorm,vCaesar/xorm,zileyuan/xorm,aviau/xorm,toophy/xorm,zileyuan/xorm