choose proper key for leanwork when sending notifications

leanworkOut.go

 }
 
 func (m *LeanworkOut) UpdateSignature() {
-	s := m.SignType + m.OrderNo + m.OrderAmount + m.OrderCurrency + m.TransactionId + m.Status + Config.LeanWork.MD5Key
+	s := m.SignType + m.OrderNo + m.OrderAmount + m.OrderCurrency + m.TransactionId + m.Status + m.getLeanworkMD5Key()
 	m.Sign = md5str(s)
 }
 
+func (m *LeanworkOut) getLeanworkMD5Key() string {
+	li, err := getLeanworkInById(m.Leanwork)
+	if err != nil {
+		log.Printf("Error determin P2P or FAT, leanworkIn = %d", m.Leanwork)
+		return ""
+	}
+	return li.MD5Key
+}
+
 func (m *LeanworkOut) add2db() (ret LeanworkOut, err error) {
 	if err = db.conn(Config); err != nil {
 		return