#289 fix the error handling when xa transaction error in prepare

src/main/java/com/actiontech/dble/backend/mysql/nio/handler/transaction/AbstractCommitNodesHandler.java

@@ -105,6 +105,11 @@ public abstract class AbstractCommitNodesHandler extends MultiNodeHandler implem
 
     }
 
+    @Override
+    public void reset(int initCount) {
+        nodeCount = initCount;
+        packetId = 0;
+    }
 
     public void debugCommitDelay() {
 

src/main/java/com/actiontech/dble/backend/mysql/nio/handler/transaction/xa/XACommitNodesHandler.java

@@ -88,7 +88,7 @@ public class XACommitNodesHandler extends AbstractCommitNodesHandler {
                     public void run() {
                         ErrorPacket error = new ErrorPacket();
                         error.setErrNo(ER_ERROR_DURING_COMMIT);
-                        error.setMessage(errorMsg.getBytes());
+                        error.setMessage(errorMsg == null ? null : errorMsg.getBytes());
                         XAAutoRollbackNodesHandler nextHandler = new XAAutoRollbackNodesHandler(session, error.toBytes(), null, null);
                         nextHandler.rollback();
                     }