Bug 154803 [regression]Cannot render document to user defined path through __document parameter
Description: Cannot render document to user defined path through __document parameter Steps to reproduce: 1. Preview a report in viewer 2. Modify url to add "__document=c:/tmp.rptdocument", this will generate report document to c disk with name "tmp.rptdocument" 3. Press enter. Expected result: Report displays correctly and the document is created. Actaul result: The document file : c:/tmp.rptdocument does not exist or contains errors.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ViewerAttributeBean.java
* 
	 * @return String
	 */
	protected String getParameterDefaultValues(
			IViewerReportDesignHandle design, String paramName,
			InputOptions options ) throws ReportServiceException
	{
		if ( design == null )
			return null;
		String defalutValue = null;
		Object defaultValueObj = null;
		
		try
		{
			defaultValueObj = this.getReportService( )
					.getParameterDefaultValue( design, paramName, options );
		}
		catch ( ReportServiceException e )
		{
			e.printStackTrace( );
		}
		
		ScalarParameterHandle parameter = (ScalarParameterHandle) findParameter( paramName );
		
		if ( defaultValueObj != null && parameter != null )
		{
			defalutValue = ParameterValidationUtil.getDisplayValue( null,
					parameter.getPattern( ), defaultValueObj, locale );
		}