Bug 140534 [Smoke]Can't changed the value of parameter use show report parameter
Details: [Smoke]Can't changed the value of parameter use show report parameter Step: 1. New a parameter. 2. Change display type to list box. 3. Insert some value into selection value and set the first value to default value. 4. Drop the parameter inro layout 5. Preview and press show report parameter, change the value and press OK. Actual result: The value can't be changed.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/BaseAttributeBean.java
* values from config file
	 */
	protected Map configMap = null;
	/**
	 * values from document file
	 */
	protected Map parameterMap = null;
	/**
	 * Abstract methods.
	 */
	abstract protected void __init( HttpServletRequest request )
			throws Exception;
	abstract protected IViewerReportService getReportService( );
	abstract protected void __finalize( ) throws Throwable;
	/**
	 * Default constructor.
	 */
	public BaseAttributeBean( )
	{
	}
	/**
	 * Constructor.
	 */
	public BaseAttributeBean( HttpServletRequest request )
	{
		try
		{
			init( request );
		}
		catch ( Exception e )