修复不兼容mysql 5.0.4的问题，jdbc 3

git-svn-id: http://code.alibabatech.com/svn/druid/trunk@474 b9813039-fb51-4c41-a8b9-e21c2acb5095

src/main/java/com/alibaba/druid/pool/PoolableStatement.java

@@ -16,7 +16,6 @@
 package com.alibaba.druid.pool;
 
 import java.sql.Connection;
-import java.sql.Driver;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.SQLWarning;
@@ -420,34 +419,7 @@ public class PoolableStatement extends PoolableWrapper implements Statement {
 
     @Override
     public final boolean isClosed() throws SQLException {
-        if (this.closed) {
-            return true;
-        }
-
-        Driver driver = null;
-        {
-            ConnectionHolder holder = conn.getConnectionHolder();
-            if (holder != null) {
-                DruidAbstractDataSource dataSource = holder.getDataSource();
-                if (dataSource != null) {
-                    driver = dataSource.getDriver();
-                }
-            }
-        }
-        // Oracle Driver 10.x is JDBC 3.0
-        if (driver != null) {
-            if ("oracle.jdbc.driver.OracleDriver".equals(driver.getClass().getName())) {
-                if (driver.getMajorVersion() <= 10) {
-                    return closed;
-                }
-            }
-        }
-
-        try {
-            return stmt.isClosed();
-        } catch (Throwable t) {
-            throw checkException(t);
-        }
+        return closed;
     }
 
     @Override