Fix METADAPT-A deadlock when closing transaction

metadapta.go

@@ -104,7 +104,7 @@ func (this *a) receive() {
 		this.transLock.Lock()
 		defer this.transLock.Unlock()
 		for _, trans := range this.transMap {
-			trans.Close()
+			trans.closeDontUnlist()
 		}
 		clear(this.transMap)
 	}()
@@ -163,9 +163,13 @@ type transA struct {
 }
 
 func (this *transA) Close() error {
-	this.incoming.Close()
+	err := this.closeDontUnlist()
 	this.parent.unlistTransactionSafe(this.ID())
-	return nil
+	return err
+}
+
+func (this *transA) closeDontUnlist() error {
+	return this.incoming.Close()
 }
 
 func (this *transA) ID() int64 {