add back SetMaxConns for compitable and set @deprecated
add back SetMaxConns for compitable and set @deprecated

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