remove rmb_fee in direct_pay, use check_optional_params
remove rmb_fee in direct_pay, use check_optional_params

lostpupil/alipay,serco-chen/alipay,yijiasu/alipay,yumikohey/alipay,FX-HAO/alipay,chloerei/alipay,denny2trasy/alipay,logchi/alipay,liupeng/alipay,greatbody/alipay,hotvulcan/alipay,jasl/alipay