Remove obsolete field

See gh-32992

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/JdbcTransactionObjectSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,9 +19,6 @@ package org.springframework.jdbc.datasource;
 import java.sql.SQLException;
 import java.sql.Savepoint;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-
 import org.springframework.lang.Nullable;
 import org.springframework.transaction.CannotCreateTransactionException;
 import org.springframework.transaction.NestedTransactionNotSupportedException;
@@ -48,9 +45,6 @@ import org.springframework.util.Assert;
  */
 public abstract class JdbcTransactionObjectSupport implements SavepointManager, SmartTransactionObject {
 
-	private static final Log logger = LogFactory.getLog(JdbcTransactionObjectSupport.class);
-
-
 	@Nullable
 	private ConnectionHolder connectionHolder;