Bug #56489 Not handling repreparation of PS

Description:
c/NET does not handle re-preparation of PS as per chapter 12.6.4 of the MySql 5.1 Reference Manual (http://dev.mysql.com/doc/refman/5.1/en/statement-repreparation.html).

How to repeat:
-

Suggested fix:
-

Please give an example test case that illustrates this problem.

Cannot repeat using C/NET 6.3.6 and the following test case:

private void bIssue50703_Click(object sender, EventArgs e)
{
    MySqlConnection con = new MySqlConnection();
    try
    {
        con.ConnectionString = "server=localhost;database=test;" +
             "user id=*******;Password=****;Ignore prepare=false";
        con.Open();
        MySqlCommand cmd = new MySqlCommand();
        MySqlCommand cmd2 = new MySqlCommand();

        cmd.Connection = con;
        cmd2.Connection = con;

        cmd2.CommandText = "DROP TABLE IF EXISTS t_issue50703";
        cmd2.ExecuteNonQuery();
        cmd2.CommandText = "CREATE TABLE t_issue50703 (id int auto_increment primary key, txt varchar(32))";
        cmd2.ExecuteNonQuery();

        cmd.CommandText = "INSERT INTO t_issue50703(id, txt) VALUES (@val1, @val2)";

        cmd.Parameters.AddWithValue("@val1", 1);
        cmd.Parameters.AddWithValue("@val2", "something");

        cmd.Prepare();
        cmd.ExecuteNonQuery();

        cmd2.CommandText = "FLUSH TABLES";
        cmd2.ExecuteNonQuery();

        cmd.Parameters[0].Value = 2;
        cmd.Parameters[1].Value = "something 2";
        cmd.ExecuteNonQuery();

        cmd.CommandText = "DROP TABLE IF EXISTS t_issue50703";
        cmd.ExecuteNonQuery();

        tbOutput.AppendText("Done!\r\n");
    }
    catch (Exception ex)
    {
        string error = ex.Message.ToString();
        error += ex.StackTrace;
        tbOutput.AppendText("=============================================\r\n" +
                            "Error!\r\n" + error + "\r\n" +
                            "=============================================\r\n");

    }
    finally
    {
        con.Close();
    }
}